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Recent molecular ecological studies have focused on how the relationships between physical and ecological factors influence marine biogeography. Comparative phylogeography using closely related species is a powerful approach to evaluate the role of ecological traits in the genetic variation of marine organisms. In the present study, we compared ecological traits and genetic variation in 3 species of the intertidal snail genusMonodontathat co-occur in the Japanese and Ryukyu archipelagoes. We found thatM. labiowas dominant in sheltered habitats andM. perplexawas dominant in wave-exposed habitats, whileM. confusashowed no habitat specificity. This indicates thatM. labioandM. perplexaarehabitat specialists regarding wave exposure, whileM. confusais a generalist.M. labioandM. perplexashowed lower genetic diversity and greater genetic differentiation among populations thanM. confusa. Our findings support the specialist-generalist variation hypothesis in a well-connected marine environment.

Margaritifera monodonta, or the Spectaclecase Mussel, is a federally endangered freshwater mussel species that has experienced a 55% reduction in range and is currently concentrated in 3 ri...

Although marine phylogeographers have accumulated knowledge of the evolutionary history of various invertebrates, there is a large bias among the taxa regarding genetic data. The order Polycladida is a typical example for which little genetic information at population level is available. Here, we focused on the polyclad flatwormStylochoplana pusilla, distributed in the Japanese Pacific coastal area.Stylochoplana pusillais known to have commensal relationships with certain intertidal snails, using snails (mainlyMonodonta confusa) as a refugee house. During low tide,S. pusillahides in the mantle cavity of snails to protect themselves from desiccation and predation. Here, we investigated the genetic structure ofS. pusillausing a mitochondrial Cytochrome Oxidase I marker and the species diversity of snails used by it. We found thatS. pusillahas high genetic diversity of its populations. WhileS. pusillashowed a significant genetic differentiation among populations, it was relatively low. In addition, we also showed thatS. pusillaused several intertidal snail species which inhabit various coastal environments. The present study suggestsS. pusillahas sufficient dispersal ability to connect among its local populations. Also, the range of available snails forS. pusillamay help the connectivity among local populations. We provide important knowledge about this invertebrate taxon with a unique ecology, which has been insufficiently studied.

Islamy RA, Hasan V. 2020. Checklist of mangrove snails (Mollusca: Gastropoda) in South Coast of Pamekasan, Madura Island, East Java, Indonesia. Biodiversitas 21: 3127-3134. Mangrove forests are crucial to gastropods providing breeding and nursery grounds, food sources, and shelter from predators. They are useful bioindicators of environmental pollution. Consequently, it is crucial to understand the species richness of gastropods mangrove environments. This study aims to provide information about the species composition of mangrove snails in the South Coast of Pamekasan (Madura Island), East Java, Indonesia. Samplings were performed at low tide from 4 stations in December 2019 using a transect (10m x 10m). All samples were identified using reference books and published journal. We found a total of 10 family consist of Assimineidae, Cerithiidae, Ellobiidae, Littorinidae, Muricidae, Neritidae, Olividae, Planaxidae, Potamididae, and Trochidae with consist of 15 Genus, i.e., Assiminea, Clypeomorus, Cerithium, Rhinoclavis, Laemodonta, Littorarina, Tenguella, Semiricinula, Nerita, Clithon, Oliva, Planaxis, Pirenella, Telescopium, and Monodonta. The most common substrate where mangrove snails were found was rocks, sandy, and around the tree and roots of mangrove. All gastropods in this study found alive during our surveys and predominantly mangrove associated. We assume that there are still many snails that have not been surveyed at the location. We suggest to the future researcher to survey through different sampling efforts and sampling methods such as quantitative or semi-quantitative methods.

Anatomical data on Solariellaobscura (Couthouy, 1838) are presented and analyzed. The main features of this species, when compared with other known trochoids, are: ctenidium with thick lamellae; enlarged ureter (that may indicate sexual dimorphism) instead of a modified urogenital papilla; odontophore very different from other trochoids such as Calliostoma, Agathistoma, Monodonta, and Gaza, with short m6, large mj and m4 pairs and absent m8 pair and posterior cartilages; esophageal valve surrounding the odontophore ventrally; anterior and mid-esophagus composed of several thin folds and a very wide cerebral ganglion. Solariellaobscura differs from Solariellavaricosa (Mighels & Adams, 1842) by having lower spire, spiral cords weaker on the base and axial rib oblique. There are no differences between S.obscura and S.varicosa in the external morphology and radula. These internal anatomical data are described for the first time for a solariellid and might improve our understanding of the relationships within this taxon.

2 of Ulva frond, hole areas ranged from 0.37 to 5.94 cm 2 , and between 4.9 and 36.2 holes were observed. Fourteen residential animal species were observed at the three evaluated sites, 75.0 (Haseom) to 408.7 individuals 100 g -1 Ulva (Pohang) per site. The dominant residential species at each site differed with Amphithoe sp. at Haseom, Monodonta spp. at Pohang, and Pagurus sp. at Woedo. The growth (frond area, wet weight) and hole number of Ulva fronds, and the number of residential animals were significantly greater in samples collected from the sheltered shore than the wave-exposed shore of Seongsan. The present results showed U. australis grew well at sheltered shores and had more holes on the fronds due to abundance of residen- tial animals. The dominant residential animals (crabs, gammaridea, and snails) were similar in the Ulva populations of sheltered and wave-exposed shores, but greater species diversity was observed at the exposed shore (18 species ver. 11 species). In conclusion, U. australis is a keystone species providing habitat to various invertebrates and frond holes are positively correlated to the number of residential animals.

Marine organisms with a planktonic larval stage can passively disperse long distance and are thus expected to have a wider distribution range and lower geographic variation. However, recent molecular phylogenetic studies have revealed that they often display a clear geographic genetic structure or even form a geographically fragmented species complex. These genetic divergences can be facilitated by the presence of dispersal barriers such as oceanic currents and/or by the limitation of suitable habitats. Using comprehensive phylogenetic analyses, we evaluate how such dispersal barriers shape genetic divergence and speciation in the intertidal snail genus Monodonta. Our phylogenetic analysis revealed various patterns of cladogenesis in Monodonta in East Asia. Genetic segregation between the Japanese and Ryukyu Archipelagos are detected in M. labio and M. perplexa perplexa. However, the relationship of geographical border and lineages does not correspond to those two because they show different habitat preference. M. labio distributed in the Japanese mainland is separated by the boundary corresponding to the point from which oceanic currents split into different directions. In contrast, species inhabiting various environments such as M. confusa are not genetically separated in Japan. In the peripheral oceanic Ogasawara Islands, two Monodonta species form each endemic lineage, although these two underwent different colonization processes to the islands. These findings suggest that the genus Monodonta has been genetically diversified around Japan, probably due to its correlations with dispersal ability, oceanic current, and habitat preferences. These factors may be effective causes for diversification of marine gastropods with a planktonic stage.

The presence of thin organic layers embedded in the nacreous layer in the shell of several species of Unionoida has been widely considered to be largely a reaction to prevent further shell dissolution once part of the shell has been corroded. Their microstructural characteristics have also been used as taxonomic characters to separate the families Margaritiferidae and Unionidae. This paper focuses on the description and interpretation of these organic layers in samples of four extant species of European Unionidae coming from acidic and alkaline waters, six extant species of Margaritiferidae, one Cretaceous Unionidae and two Cretaceous Margaritiferidae species. Our results demonstrate that organic layers have characterized species of Unionoidea at least since the Cretaceous and occur in specimens coming from both acidic and alkaline waters. Moreover, the presence of these layers in noncorroded shells can be interpreted as a preventative or ‘prophylactic’ measure against corrosion. Their thickness is the only useful character verified to separate the two families. In the Margaritiferidae, organic layers were found to be present in Margaritifera margaritifera, M. valdensis, M. idubedae, M. laosensis, M. laevis and M. monodonta, and absent in M. auricularia and M. marocana. In Unionidae, they appear in Protopleurobema numantina, Potomida littoralis and in some individuals of Unio mancus, U. delphinus and U. tumidiformis. We argue that organic layers played a fundamental role in shell protection during the invasion of freshwater by the earliest Unionoida, while today they function to improve fitness in acidic water in some species.

With the aim to assess the gastropod mollusk Monodonta turbinata as biomonitor of trace metal pollution in seawater of a central Tyrrhenian ecosystem (Pontine Islands archipelago, Italy), one hundred individuals were collected in five strategic locations in two sampling campaigns during 2011 and 2012. Concentrations of Cd, Cr, Cu, Ni, Pb and Zn were measured in the mollusks and in seawater samples (soluble fraction) collected in the same sites in order to obtain the respective concentration factors (CFs). Two-way ANOVA was applied to verify the presence of site and time effects. Then, the significant time effect due to the two sampling campaigns was eliminated by defining six new variables (one for each metal) and applied multivariate statistics in order to obtain more reliable results. Subsequently, the levels of metal contamination of Pontine Islands were compared with the naturality concentration ranges (control charts) previously established for the Tyrrhenian Sea (Italy; Conti et al. in Environ Sci Pollut Res 22:3640–3651, 2015). Monodonta resulted to be a very good accumulator of Cd (CF = 2100) and good accumulator of Cr (CF = 1570), Pb (CF = 1000) and Zn (CF = 1160). Levels of Cd, Ni, Pb and Zn in Monodonta from 2011 to 2012 decreased in the range from −22.8 of Pb to −41.9% of Cd in Ponza Frontone, Ponza Cala Fonte and Ponza harbor sites; on the contrary, Cr and Cu showed an increase of 3.4 and 63.7%, respectively, in the same sites from 2011 to 2012. A not univocal trend of metal bioaccumulation patterns between the two sampling campaigns (2011–2012) in the selected sites was observed. No one site resulted to be evidently more contaminated than another (i.e., Ponza harbor site as expected). In general, the metal levels in these marine areas are low and within the previously established baseline ranges for Tyrrhenian Sea (control charts). The results here reported can be used as a reference baseline levels for comparison with other marine geographical areas.

We isolated 29 microsatellite loci from Cumberlandia monodonta, a freshwater mussel species that has experienced population declines throughout its range. Seventeen loci were polymorphic, with 3–13 alleles, observed heterozygosity values of 0.375–1.00, and 38% of alleles found in more than one population. These loci should be useful for describing population genetic diversity, which will facilitate ongoing conservation efforts for C. monodonta.

The first data about the genus Cryptazeca were provided by Folin & Berillon (1877a) when they described azeca monodonta based on the study of two empty shells collected near Bayonne in southwestern France. Later they collected some live specimens and established the genus Cryptazeca for it, after study of its anatomy (Folin & Berillon, 1877b, 1891). This genus was included together with Ferussacia, Cecilioides, azeca (with Hypnophila), Cochlicopa, and five additional genera in the family Ferussaciidae (Pilsbry, 1908). Watson (1928) noticed that Ferussacia and Cecilioides had a sigmurethrous excretory system and placed them and the family Ferussaciidae in the infraorder Sigmurethra, whereas Steenberg (1925) and Zilch (1959) placed azeca, Cochlicopa, and Hypnophila in the family Cochlicopidae (infraorder Orthurethra). New live specimens of the genus Cryptazeca were collected in 1987 and its excretory system described as being of the orthurethrous type by Gomez & Angulo (1987). Consequently, these authors proposed to change the taxonomic position of this genus to be placed with azeca, Cochlicopa, and Hypnophila in the family Cochlicopidae. Detailed anatomical and histological studies of the reproductive system also corroborated the close relationships among Cryptazeca, azeca, and Hypnophila (Gomez & Angulo, 1987, 1990; Gomez, 1990b, 1991). Nevertheless, Schileyko (1976) considered that orthurethria was probably a primary condition for Stylommatophora, which could be retained in some taxa outside orthurethral groups. This led again to the placement of Cryptazeca within the family Ferussaciidae. As a result, the classification followed by the CLECOM project (Bank et al., 2001; Falkner et al., 2001) placed Cryptazeca (Cryptazecinae) with Ferussacia, Cecilioides, and Hohenwartiana (Ferussaciinae) within the Ferussaciidae, in the superfamMALACOLOGIA, 2010, 52(1): 163−168

Trail following behaviour and pedal mucus production were investigated in the mid-shore topshell, Monodonta labio (Linnaeus) in Hong Kong. On the shore, individuals exhibited both conspecific and self trail following while awash on ebb and flood tides, although fidelity to resting sites during emersion on successive days was low. In the laboratory, animals that encountered trails that had been aged on the shore for different periods showed similar patterns of movement (distance moved, speed and tortuosity) suggesting that degradation of cues in the mucus that animals responded to did not occur until > 3 days post-deposition. Animals moved faster, with a lower rate of radular rasping, on freshly laid mucus trails than on a biofilm-covered substratum and did not change their speed when moving over aged (biofilm-covered) mucus compared to fresh mucus. Mucus production rates were similar when animals were crawling on vertical or horizontal surfaces, but significantly more mucus was produced when animals were emersed than when submerged. Mucus trail profiles were of variable thickness, but ‘double’ mucus trails (marker + tracker trails) did not contain significantly more mucus than ‘single’ trails (marker mucus only) and were considerably thinner than single trails suggesting tracker snails utilized mucus laid by marker snails, reducing their own deposition of mucus. Thus, while M. labio do not appear to utilize trails for orientation or refuge location, snails that follow trails have the potential to save energy through reducing mucus production or to gain energy through mucus ingestion. Given the role of pedal mucus production in the overall energy balance of gastropods, such energetic benefits are considerable and may have implications for the life history of the snail.

A total of 360 of the midlittoral gastropod Monodonta dama (Phillipi, 1848) from the rocky shores in the Gulf of Aqaba, Red Sea, were studied for age, growth and shell morphometrics. The results show that M. dama may survive for five years. The mean observed length at each of the five age cohorts was 0.605, 0.977, 1.328, 1.568 and 1.934 cm. Theoretically, using Von Bertalaffy`s and Richard`s growth formulae, the maximum length of this snail may reach 2.772 and 2.210 cm, respectively. The annual observed increase in length ranges from 0.240 to 0.372 cm. Theoretically, the increase ranges from 0.180 cm in old snails to 0.472 cm in young ones using the VBGF and from 0.134 to 0.260 cm using RGF. The relationships of the shell length to shell width, aperture length and aperture width are linear. The ratios of the shell length to shell width, aperture length and aperture width increase with age. This may indicate that this snail become more elongate with age.Moreover, the ratio of the shell width to aperture width increases with length. Shell and dry body weights averaged 705 and 475 mg, respectively. The relationships of the shell length to shell and dry body weights are curvilinear. However, the relationships of the shell length to shell width, aperture length and aperture width are linear. The relative coefficient of condition (Kn) which measures the progression of body weight and length was 0.334.

The systematics of topshells (family Trochidae) is currently unresolved: at present even the generic boundaries within this group are poorly defined. In this study, we used sequence data of two mitochondrial genes (16S and cytochrome oxidase 1, COI) and one nuclear gene (actin) to resolve the phylogeny of a closely related subgroup of the Trochidae, 30 species of largely Southern Hemisphere monodontine topshells. The phylogenies constructed revealed five well-supported generic clades: a South African clade (genus Oxystele Philippi, 1847), which lay basally to four internal Pacific clades (genera Chlorodiloma Pilsbry, 1889; Monodonta Lamarck, 1799; Austrocochlea Fischer, 1885; and Diloma Philippi, 1845). The molecular phylogenies constructed in this study shed light on previously unresolved relationships between different groups of topshells, allowing for the first time assignation (based on DNA sequence) of clearly defined, well-supported taxonomic and nomenclatural classification of monodontine topshells species. Austrocochlea crinita (Philippi, 1849), A. odontis (Wood, 1828), A. adelaidae (Philippi, 1849), and A. millelineata (Bonnet, 1864) are placed in the genus Chlorodiloma , which we resurrect from synonymy with Austrocochlea . The Japanese M. confusa Tapparone-Canefri, 1874 is treated as a separate species from M. labio (Linne, 1758). Melagraphia Gray, 1847 is synonymised with Diloma and its sole member, M. aethiops (Gmelin, 1791), along with A. concamerata (Wood, 1828), is transferred to that genus. The Juan Fernandez endemic D. crusoeana ( Pilsbry, 1889 ) (Pilsbry, 1889) is synonymised with D. nigerrima (Gmelin, 1791). We find that morphologically cryptic species are not necessarily close genetically.

To test the hypotheses explaining the sex expression of the immobile snail Quoyula monodonta, which inhabits the surfaces of the branching coral, Pocillopora eydouxi, the size, sex, gonad development, penis length and the composition of neighboring individuals were investigated between November 1994 and August 1995 in southern Taiwan. Although the snails often aggregated and formed patches, more than 50% were solitary. Females were larger than males both within a snail patch and in the whole population, but the overlap in size range was wide. The males were generally accompanied by females, whereas most females were solitary. Females were rarely (6%) found in the same patch with another female, but 35% of the males had male neighbors. Most juveniles found were also solitary. The composition pattern within a patch cannot be explained by random sampling. Gonad development of an individual was dependent on the presence and the sex of its neighbors within the same patch; the penis length of males also depended on the presence of neighbors. These phenomena suggest that an individual is sensitive to its neighbors. No individuals in the process of sex change were ever found from histological studies of the gonads. Neither the hypothesis that the sex of recruits determines their habitats, nor the hypothesis that there is strict protandric sex-change is supported. The results, however, are all clearly compatible with the hypothesis that the snail has labile sex expression. In the presence of existing females in a patch, recruits are more likely to develop into males, whereas recruits starting a new patch grow to a larger size before developing into females directly. The labile sex expression of Q. monodonta is the only such report in neogastropods.

Accumulation of Cd, Co, Cr, Cu, Fe, Mn, Ni and Zn was studied in the sediments, Cymodocea nodosa leaves, roots and stems and in two gastropods from an area adjacent to a ferro-nickel smelting plant and a control site on the east coast of Greece. In the sediment, the metals, with the exception of Cu, have significantly higher concentrations in the polluted than in the clean site. There is a tendency for C. nodosa tissues in the polluted area to have higher concentrations of metals although the differences are not always statistically significant. Co, Mn, Ni and Zn are in higher concentrations in the leaves than in the other tissues, a trend more obvious in the polluted site. Concentrations of metals in the viscera of the gastropods Cerithium vulgatum and Monodonta mutabilis are higher than in the muscle (except for Cd) and significantly higher in the animals from the polluted site. It is suggested that Mn is taken up from the water by C. nodosa leaves, which in the form of detritus enter C. vulgatum. Mn concentrates in the viscera of C. vulgatum in the form of granules. Zn follows the same route with additional amounts being taken by C. vulgatum directly from the water. © 1998 Elsevier Science Ltd. All rights reserved

The Mediterranean trochid gastropods currently known as Monodonta mutabilis (Philippi, 1846) and Gibbula richardi (Payraudeau, 1826) are shown, on both morphological and electrophoretic grounds, to be sibling species, and therefore congeneric. The generic name Phorcus Risso, 1826 should be used for these species, which may be more closely related to the Mediterranean Trochocochlea species than to other species classified in Gibbula. The oldest appropriate genus-group name for the Mediterranean species currently classified as Monodonta (M. articulata, M. turbinata) is Trochocochlea MOrch, 1852. The earliest type species designation for Osilinus Philippi, 1847 is that of Trochus constrictus Lamarck, 1822 by Herrmannsen (1847), which would make Osilinus a valid senior synonym of the widely used name Austrocochlea Fischer, 1885 and not of Trochocochlea as commonly accepted. A ruling of the International Commission on Zoological Nomenclature will be sought for the case.

Monodonta labio (Gastropoda: Trochidae) occurs in a wide tidal zone on a boulder-covered shore in Amakusa, Japan. To investigate sources of variation in reproductive output within a population, the fecundity ofM. labio was estimated. Regressions of gonad egg counts on shell width were calculated from samples collected bi-weekly at three tidal zones: high, mid and low intertidal. Seasonal fluctuations in the regression revealed that individual females spawn at least three times a year. Variation in fecundity between the three tidal zones was not detected at any time in standard 12 mm snails. Due to the high growth rate in the low zone during the reproductive season, annual fecundity in the low zone was larger than that in the high and mid zones. Thus, tidal zone variation in fecundity ofM. labio was a result of growth variation between tidal zones.

Marine snails excrete metals via the gut. The sediment-feeding, tower shell Cerithium vulgatum, from a polluted environment, accumulates Cr and Ni to 3500 ppm dry weight in the faecal pellets. Pellets from C. vulgatum and the grazing, top shell Monodonta mutabilis were incubated in surface and deeper anoxic layers of clean and metal-polluted sediment. Pellets retained the original load of metals and in some cases gained Ti, Cr, Mn, Fe and Ni. Effects were modified by sediment properties. Pellets of C. vulgatum are durable, membrane-bound structures and they reduce metal bioavailability to food chains by compartmentalization. Intracellular, phosphate granules bind metals in digestive glands of snails and they are excreted via the gut and faecal pellets. These granules were extracted from digestive glands of both species of snail and incubated in the same sediments. Magnesium phosphate granules from M. mutabilis dissolved but calcium/metal phosphate granules from C. vulgatum remained; they had differentially retained or lost Mn, Fe, Co, Ni and Zn according to the type of sediment.

Coastal rock bioerosion research is well established. Otherwise there is the need to improve the way in which bioerosion rates are calculated. Since the findings of McLean (1967), it has been assumed that the dry weight of pellets collected after 24 hours provides an estimate of the amount of organism daily erosion. This is an assumption that relies largely on initial experimental procedures lacking any empirical ascertainment. This paper assess what is the transit time of the rock fragments through the intestine of the gastropod Monodonta articulata, and the implications of applicability of this temporal framework to the computation of a more precise estimation of the bioerosion throughout laboratory experiments. Our results suggest that for the gastropod Monodonta articulata, the major part of the eroded and ingested rock is defecated during feeding time. According to this, the confidence of bioerosion rates values calculated by means of faecal pellet collection based on 24-hour time frame can be concluded. Erosion rates for M. articulata activity in limestone rock samples have been estimated to range between 8.00 mg·ind-1·day-1 to 10.10 mg·ind -1·day-1. © Coastal Education & Research Foundation 2013

Growth of Monodonta lablo (Linne) (Gastropoda: Trochidae) was investigated bimonthly for a period of 1 yr by quadrat sampling and mark-recapture on a moderately exposed boulder shore in Amakusa, South Japan. Linear regression was calculated for shell width at recapture on shell width at release. Growth in the high zone was slower than in the mid and low zones and decreased as shell width increased. Estimated growth curves fit well with the observed growth curves of individual snails. Seasonal growth patterns of juvenile (58 mm) snails may be affected by seasonal fluctuation of micro- algal abundance. Due to reproduction, growth of large snails decreased in summer. Tidal level varia- tion of growth rate caused large variation in growth curves in middle-sized snails (ca 10 rnm shell width), because of their wide range of distribution, which was related to vertical migration on the shore. Simulated growth curves showed that 8 mm snails in the high zone reached asymptotic size (ca 13 mm) 1 yr later than snails in the mid and low zones. In small (ca 6 mm) and large (ca 13 mm) snails, less van- ability in observed growth curves was explained due to their limited ranges of distribution. This study demonstrates that variation in growth rate is attributable to sue-specific distribution on a shore and indicates how migration expands size variation within a single age group.

In any polluted marine environment, different invertebrate species contain markedly different concentrations of heavy metals. Primary producers take metals from seawater, but animals take additional metals from diets of animals, plants and detritus. Metals in a dietary organism of a food chain have varying reactivities and they follow different biochemical pathways. Excess metals are bound by ligands to form insoluble compounds within cytological compartments. These metabolic systems prevent the disruption of normal biochemical reactions by metals. The present work on Mediterranean invertebrates, initiated in Greece in 1993, used digestive glands from three species of marine snail,Monodonta mutabilis (Philippi),Cerithium vulgatum (Bruguiere), andMurex trunculus (Linnaeus) as prey tissue, and hermit crabsClibanarius erythropus (Latreille) as predators; the digestive glands and faecal pellets from all animals were analysed by atomic absorption spectroscopy and x-ray microanalysis. Most metals detoxified by the snails are unavailable to the crabs and they pass straight through the gut and appear in the faecal pellets. This applies to significant proportions of the manganese, nickel, copper, zinc and silver which are bound electrostatically to phosphate or covalently to sulphur within membrane-bound intracellular compartments. Cadmium and chromium are transferred to the crabs. In digestive glands of snails, cadmium is bound to soluble highsulphur protein in the cytosol; the cytology of chromium in these animals is not known.

LT50 values obtained for Monodontaturbinata exposed to heavy metal ions were as follows: 25.2 days after exposure to final concentration of 1.0ppm Cd+2; 21.2 days for 0.1ppm Hg+2; 25.2 for 0. 5ppm Cr+3 and 16.8 days for 0.5ppm Cr+6, compared to 32.8 days for the control. The final concentrations of metal ions in the mollusc tissue increased by 20 times in the Hg+2, and by 10 times in the Cd+2 treated Monodonta, compared to the untreated control. The normal contents of cytochromes be and P450 in Monodontaturbinata digestive gland microsomes were 195±51 and 58±20 nmol/mg protein, respectively. NADPH-cytochrome c reductase activity was 5.9±3.0 nmol/min/mg protein. Exposure to all heavy metal ions had a destructive effect on the two hemoproteins, especially on cytochrome P450, and a pronounced impact on NADPH-cytochrome c activity which was reduced to about 50% in the treated mollusc. No alarming concentrations of metal ions could be detected in Monodontaturbinata collected from different sites along Israel Mediterranean coast.

The effects of copper and chromium are studied on the cosmopolite marine prosobranch Monodonta turbinata (Born). The influence of Cu and of the mixture Cu + Cr was tested by the determination of the LC50 (48 h), the LT50, the respiration and bioaccumulation rates. The tested concentrations of metals caused a significant reduction of the respiration rate of Monodonta. Cu accumulates progressively in the tissues of the prosobranch proportionally to the Cu concentrations of the tested media. In all experiments [LX50 (48 h), LT50, oxygen consumption and bioaccumulation] when Cu and Cr act jointly, an antagonism is observed: the mixtures caused less pronounced effects than Cu and Cr acting alone. Generally Monodonta was found to be much more sensitive to Cu than other benthic species.

Several behavioural, physiological and morphological parameters were studied in two marine gastropods to better define niche differences between the species. M. turbiformis is adapted to a broader more variable niche where as M. turbinata has more stringent niche requirements. This study demonstrated that M. turbinata as compared with M. turbiformis has: a) greater foot muscle strength, b) shorter more squat shell form, c) greater body weight per shell weight and d) greater foot size per body weight. M. turbiformis has a) greater resistance to desiccation and low temperature and b) a more slender shell form. Qualitatively, M. turbiformis appears less effected by elevated temperatures to 40° C. In the laboratory, M. turbinata is more sensitive to crowding. In the field, M. turbinata is found principally in high energy situations with respect to surf action or water flow on or over rocks to which it is attached. On the other hand, M. turbiformis is exclusively found in relatively quiet, shallow wat...

Trace elements were analyzed in organisms collected at five sampling stations along coastal areas of Linosa Island, Sicily (southern Tyrrhenian Sea, Italy). Concentrations of Cd, Cr, Cu, Pb, and Zn were measured in Posidonia oceanica L. Delile tissues, the two brown algae Padina pavonica (L.) Thivy and Cystoseira sp., and the two gastropod mollusks Monodonta turbinata Born and Patella caerulea L. Seawater samples were also collected at each site to assess soluble metal concentrations and to gain relevant information on their bioaccumulation ability. Data were processed by multivariate techniques, such as principal component analysis (PCA) and linear discriminant analysis on PCA factors. The scoreplots obtained showed that the pollutant distribution is more significantly correlated with species than with sites. For seaweeds, P. oceanica was associated with higher Cd, Cu, and Zn levels; Padina species had higher Cr concentrations, and Cystoseira had higher Pb levels. For mollusks, Monodonta species had high concentrations of Cu and Cr and Patella species were associated with Cd. Some general metal bioaccumulation patterns are described but no one sampling site was more contaminated than the others. The hypothesis of Linosa island serving as a reference ecosystem for baseline trace metal levels in southern Tyrrhenian areas is indeed supported by the statistical comparison among other southern Tyrrhenian ecosystems performed with Kruskall Wallis and Mann-Whitney tests. For P. oceanica leaves, P. pavonica, M. turbinata, and P. caerulea, this study confirms their usefulness as possible cosmopolitan biomonitors of trace metals in marine Mediterranean areas.

Several recent studies have shown the potential value of chloroform-soluble fluorescent age pigments (FAPs) in determining the age of marine invertebrates with no permanent hard parts. The primary assumption in estimating age from FAPs is that there is a linear (or at least monotonie) increase in FAP content with time. We have tested this assumption with the trochid gastropod Monodonta lineata , a species whose age can be established unequivocally from shell growth checks. Samples of 10 age classes (1.5–10.5 yr) were obtained and FAPs extracted from lyophilised cerebral ganglia and digestive gland. The fluorescence emission spectra were similar to those reported for other organisms, though the wavelength of maximum intensity varied with tissue, sex and age. Cerebral ganglia often showed two major emission peaks, digestive gland only one. Thin-layer chromatography indicated that at least three fluorescent compounds were present in the extracts. Digestive gland total FAP content did not vary for the first 5 yr of growth, but then trebled during the next 5 yr. The tissue concentration of FAP showed no statistically significant trend. Cerebral ganglia total FAP content increased during the first 5 yr then remained constant for the next 3 yr before declining. There was a steady decline in the concentration of cerebral ganglion FAP throughout life. These patterns indicate a complex relationship between FAP content and calendar age, and indicate that (at least in Monodonta ) FAPs have little practical value for determining age.

Cadmium, Co, Cr, Cu, Fe, Mn, Ni, and Zn were measured by atomic absorption spectroscopy in the digestive gland of the marine gastropods Cerithium vulgatum, Monodonta spp., Murex trunculus, Conus mediterraneus , and Patella coerulea , sampled during different seasons at four sites near a ferro-nickel smelting plant and two control sites on the east coast of Greece. Near the smelter there were higher concentrations of all metals in Cerithium (except Cu) and Murex , and of Ni and Co in Monodonta , compared with the control sites, which indicated that the plant contaminated the environment. The animals from the contaminated area showed marked differences in concentrations which were associated both with the genera and the sites, while there were no consistent seasonal variations.

Monodonta turbinata B. and Patella caerulea L. were evaluated as possible biomonitors of trace metal contamination in marine coastal areas. These species are marine gastropod molluscs; they are distributed in all coastal areas of the Mediterranean sea and are easy to identify and available all year round. They have the necessary prerequisites for use as biomonitors. The first aim of this preliminary survey is to evaluate the concentrations of Cd, Cr, Cu, Pb and Zn present in soft tissues of the selected species. Samples were collected in the tidal zone (1-2 meters depth) in a possible reference ecosystem (Linosa island, Sicily, Italy). Five coastal stations were selected according to the species availability. The second purpose was to establish the validity of these two gastropod species as bioaccumulators. The station number 4 (Pozzolana di Ponente) is the only site in Italy where the sea turtle Caretta caretta, annually deposes her eggs; thus this station is of a particular ecological relevance. In order to test the bioaccumulation capabilities of these biomonitors seawater samples were collected in each site to assess soluble metal concentrations and then CFs. Seawater samples were collected appropriately in a 6-month period of sampling in the selected stations. Statistical multivariate analyses, PCA, were applied to test the differences between metal concentrations in different sites and species. Results showed high results (CFs) with respect to the concentrations in marine waters (soluble fraction). This confirmed the suitability of these species for biomonitoring purposes. PCA analysis showed clearly two separated patterns of bioaccumulation (i.e. Patella and Monodonta) and no significant differences (p = 0.05) for trace metal accumulation were obtained between the studied sites. This finding agrees with the hypothesis of this island as reference ecosystem for intraspecific comparison within Tyrrhenian areas. www.witpress.com, ISSN 1743-3541 (on-line) © 2006 WIT Press WIT Transactions on Ecology and the Environment, Vol 88, doi:10.2495/CENV060011 Environmental Problems in Coastal Regions VI 3

Revisão taxonômica das espécies de abelhas do gênero Lestrimelitta Friese (Hymenoptera, Apidae, Meliponina) que ocorrem no Brasil. Com base em caracteres morfológicos, como aqueles relacionados com a pilosidade, o formato do espiráculo propodeal, as distâncias interorbitais e o comprimento do esporão mesotibial, são reconhecidas catorze espécies, seis das quais novas para a Ciência: L. ciliata. sp. nov., L. maracaia sp. nov., L. similis sp. nov., L. spinosa sp. nov., L sulina. sp. nov. e L. tropica sp. nov. São designados lectótipos para Trigona (Lestrimelitta) limao var. rufipes Friese, 1903 e Trigona (Lestrimelitta) limao var. rufa Friese, 1903. O macho de L. limao (Smith, 1863) é descrito pela primeira vez. É apresentada também uma diagnose das seguintes espécies: L. ehrhardti Friese, 1931; L. glaberrima Oliveira & Marchi, 2005; L. glabrata Camargo & Moure, 1989; L. monodonta Camargo & Moure, 1989; e L. nana Melo, 2003. São apresentados chaves de identificação para operárias e machos, ilustrações e mapas de ocorrência. The species of Lestrimelitta present in Brazil are revised. Fourteen species are recognized, six of them described as new: L. ciliata. sp. nov., L. maracaia sp. nov., L. similis sp. nov., L. spinosa sp. nov., L. sulina. sp. nov. and L. tropica sp. nov. The main morphological characters used to distinguish the species are pubescence, shape of the propodeal spiracle, the interorbital distances and size of the midtibial spurs. Lectotypes for Trigona (Lestrimelitta) rufa Friese, 1903 and Trigona (Lestrimelitta) rufipes Friese, 1903 are designated and redescribed. The male of L. limao (Smith, 1863) is described for the first time. The following additional valid species are diagnosed and their distinctive characters presented: L. ehrhardti Friese, 1931; L. glaberrima Oliveira & Marchi, 2005; L.glabrata Camargo & Moure, 1989; L. monodonta Camargo & Moure, 1989 and L. nana Melo, 2003. Identification keys for workers and males, maps of geographic records and illustrations are presented.

In order to gain more information on the possible use of four gastropod species as metal biomonitors for the Mediterranean area, the influence of body weight upon Cd, Cr, Cu, Pb and Zn concentrations was studied in specimens collected at locations with different degrees of environmental pollution. The selected species were the marine snails Monodonta turbinata Born and Monodonta mutabilis Philippi, and the limpets Patella caerulea L. and Patella lusitanica Gmelin. Significant differences between metal concentrations in individuals from different stations were tested by ANCOVA on log-transformed data with log body weight as covariate. For all species a positive correlation between metal concentrations and body weight was observed, which means that the largest individuals contained the highest levels of metals. The inclusion of body weight as covariate in the statistical analysis explained from 81% to 99% of the metal variability within the organisms and enabled the achievement of improvements in the detection of differences among sites. The four selected species provided a rather univocal picture of bioavailable metal loads at the different stations of the experimental area. Except for Cd, the metal concentrations recorded at the clean stations were found to lie in the range of the lowest values reported in the literature and can be employed as useful background levels which can be referred to for intraspecific comparison within the Mediterranean area. It is concluded that in view of its distribution, unambiguous identification, resistance to pollution and accumulation patterns M. turbinata has considerable potential as a biomonitor of trace metals over the Mediterranean.

Gill marsupia of Cumberlandia monodonta were observed to contain early developmental stages on 27 October 1982. This occurrence, in conjunction with histological examination of gonads from several specimens, documents the first record for autumnal reproductive behavior in C. monodonta, and lends credence to previous speculation that biannual periodicity occurs in this species. Smith (1976, 1978, 1988) systematically examined gametogenesis and reviewed brooding periodicity within the North American Margaritiferidae. However, information concerning margaritiferid reproductive biology remains sparse. Howard (1915) reported a single vernal brooding female of Cumberlandia monodonta (Say, 1829) and briefly described that individual's glochidia (also see Surber, 1915). These data are augmented by the discovery of an autumnal brooding female C. monodonta and histological examination of gonadal tissues from several preserved specimens collected at different localities. MATERIALS AND METHODS Several individuals of Cumberlandia monodonta (obtained from Meramec River, Times Beach access, 3 km east of Eureka, St. Louis County, Missouri, 27 October 1982) were maintained for several days in aquaria. During this period, one individual discharged large quantities of a mucus-like substance from its excurrent siphon. This material was collected immediately and examined microscopically. Forty additional specimens in collections of the University of Massachusetts at Amherst (UMA), Thomas M. Freitag (TMF), and one of the authors (MEG) were available for histological analysis of gonad activity (Table I). Mussels had been preserved either by fixation in 10% formalin, followed by 70% ethanol, or in alcohol without previous fixation. A portion of the viscera of each specimen was embedded in paraffin and sectioned at 8 ,m. Five sections from each specimen were hydrated to water, stained with Ehrlich's hematoxylin and eosin, dehydrated, and mounted. 1 The Tennessee Cooperative Fishery Research Unit is supported jointly by the U.S. Fish and Wildlife Service, Tennessee Wildlife Resources Agency, and Tennessee Technological University. Additional funding was provided by the Center for the Management, Utilization, and Protection of Water Resources, Tennessee Technological University. TRANS. AM. MICROSC. Soc., 109(4): 407-411. 1990. ? Copyright, 1990, by the American Microscopical Society, Inc. This content downloaded from 157.55.39.189 on Fri, 09 Dec 2016 05:30:12 UTC All use subject to http://about.jstor.org/terms TRANS. AM. MICROSC. SOC.

The effects of a nonionic detergent and also of crude oil-detergent mixtures in aqueous solutions were tested by allozyme frequencies at six loci in the Mediterranean marine gastropod Cerithium scabridum Philippi 1849. Our results indicated differential survivorship of allozyme genotypes for both detergent alone and for crude oil-detergent mixtures. This statement is true for all the loci involved in the study. When analyzing each locus separately, two of the six loci (phosphoglucose isomerase and alkaline phosphatase) did not show differential survivorship in detergent pollution. But analyzing the genetic complex involving these two loci we found differential survivorship of specific genotypes. These results reflect the adaptive nature of some PGI genotypes in these marine gastropods and seem inconsistent with the neutral theory of allozyme polymorphisms. Furthermore, these findings suggest that allozyme variants, either singly or in a two-locus structure, demonstrate a differential tolerance to these organic pollutants and can, therefore, be used as detectors of organic pollutants in the sea, as we earlier showed for single loci in two other species of marine gastropods, genus Monodonta (Lavie et al., Environ. Res. 35: 270–276 (1984).

Strontium concentrations have been determined in the outermost portions of shells of Patella coerulea, Monodonta articulata and M. turbinata. The incorporation of Sr into the carbonate seems to be influenced by the rate of growth of shells and by environmental temperatures, besides the Sr/Ca ratio in seawater. Temperature and growth rate may act either alternatively or concurrently; the latter is the case for Patella in the whole annual cycle, and for both Monodonta species during the higher temperature interval (18°–25°C). In the lower temperature interval (13°–17°C), the polymorphic composition of M. articulata shells exerts a primary control on Sr contents, whereas in M. turbinata the ratio Sr/Ca seems to be controlled by environmental temperatures, in a thermodynamic sense.

This paper presents a critical assessment of Killingley's approach to the determination of month of collection of marine molluscs by prehistoric people. The basis of the method is careful oxygen isotope measurements made in successive growth increments in the shells. We have analyzed specimens of Monodonta and Patella collected live on the coast of northern Spain, in conjunction with seasonality studies on molluscs from prehistoric sites in the neighborhood. These studies confirm the necessity of making careful analyses of each species under consideration. Given the significance both of interspecies differences and of climatic variability on timescales from a year upwards (particularly important in Killingley's area), we conclude that his apparent accuracy of ± a month is illusory.

Three species of archaeogastropod mollusc, Monodonta lineata (da Costa), Emarginula reticulata Sowerby and Patella vulgata L. were selected as representative members of the Trochacea, Fissurellacea and Patellacea, respectively, for a comparative anatomical and ultrastructural study of the excretory system. Primary urine formation takes place by filtration of blood through the walls of the paired auricles in Monodonta and Emarginula and of the single auricle and ventricle in Patella . Urine then passes to right and left kidneys along the renopericardial canals. Contrary to earlier reports the two kidneys are different in structure and function in all three species, the larger right kidney retaining the primitive function of nitrogenous excretion, the left having a predominantly resorptive role and with a capacity to abstract from the blood solutes of larger molecular mass. The difference in the size of the two kidneys is exaggerated in Patella and Emarginula as a consequence of partial restoration of bilateral symmetry in these limpets. It has been possible to demonstrate at the ultrastructural level that the minute left kidney of Emarginula is functional. The vacuolated epithelial cells of the right kidney contain layered excretory spherules composed of purines, melanin and ferric iron in different proportions in the three genera. There is close similarity in the ultrastructural organization of these cells in Monodonta and Emarginula , but those of Patella show marked differences and their excretory spherules contain a higher proportion of melanin. The position of the left kidney in the mantle skirt, as exemplified by Monodonta , is believed to have arisen in the earliest gastropods correlated with the development of helical coiling. This was accompanied by a change in its blood vessels. It has lost its afferent renal vein, which primitively would have carried deoxygenated blood from the viscera, an arrangement which persists in the right kidney. The left efferent renal vein is reduced in Monodonta and lost in Patella and Emarginula . A new vessel has arisen linking left auricle and left kidney and there is evidence to suggest that it carries post-branchial oxygenated blood. It is believed to serve as both an afferent and major efferent route. The physiological implications of this change in the blood supply are discussed and held to be responsible for the functional differences between the two kidneys, creating conditions in the left which favour resorption of organic solutes and ions, and leaving the right kidney with the primary role of nitrogenous excretion. The evolution of the nephridial gland is examined in this context and is also believed to be correlated with the change in the blood supply to the left kidney. Ultrastructural evidence is given in support of its suggested resorptive function. The significance of the differences between right and left kidneys of archaeogastropods is discussed in relation to the evolution of the monotocardian excretory system, and the possible phylogenetic relationships of the groups of archaeogastropods are considered.

Magnesium, temperature and rate of growth interrelations are studied in the shell material of three gastropod species: Patella coerulea, Monodonta turbinata and M. articulata . Mg and temperature are correlated positively in the shell calcite of Patella coerulea and Monodonta articulata , and negatively in the aragonite of M. turbinata shells. The correlations are often statistically significant at a high level of confidence and can be used as tools for ecological and paleoecological investigations. Temperature seems to be the main causal factor that controls Mg incorporation into the shell calcite, whereas, in the aragonitic M. turbinata shells, the rate of growth appears to play a determinant role on Mg concentrations.

The oxygen consumption of inactive animals of four species of Mediterranean trochid was measured in air and sea water at temperatures commonly recorded on the shore. The loss of mantle cavity fluid significantly lowered the aerial oxygen consumption of all four species. The aquatic oxygen consumption of the four species after 12 h settlement in the respirometer was not significantly different from that measured after 1 h. The high-shore Monodonta lurbinata (Born) and M. articulata (Lamarck) experience a maximum of 60 to 70% aerial exposure, wide temperature fluctuations, and can maintain an aerial rate of oxygen consumption similar to the aquatic rate. They have temperature dependent rates of oxygen consumption with similar Q 10 values in both air and water between 20 and 30°C. The low-shore Gibbula richardi (Dayraudeau) and G. rarilineata (Michaud) are characterized by a low maximum percentage aerial exposure, a more stable thermal environment, an aerial rate of oxygen consumption lower than the aquatic rate, temperature dependent respiration rates between 20 and 30°C in sea water but a temperature coefficient not significantly different from 1 in air. These patterns of oxygen consumption are reflected in the 50% survival times of the trochids in air at 25°C. The pattern of respiration in air and water of a wide range of intertidal gastropods has been related to the maximum percentage aerial exposure experienced on the shore.

Mineralogical and morphological modifications through a whole annual cycle in shells of Monodonta articulata, Monodonta turbinata and Patella coerulea have been investigated and related to temperature variations. The polymorphic composition of Ca-carbonate, both in the last-formed portion and in the whole shell, appears to be correlated with temperature in M. articulata; the correlations are usually significant, except for the largest shells, at a high level of confidence and their use as a paleoecological tool is suggested. Also, the thickness of the shells is correlated with temperature, both in M. articulata and M. turbinata and such a correlation could be used in paleothermometry investigations. Patella coerulea shells do not show much sensitivity to temperature and the correlation found with aragonite percentages seems too weak to be used confidently in paleoecological investigations, while the morphological parameters are not correlated with temperature at all.

The trochid snail Monodonta articulata Lamarck was exposed to mercuric sulphate at concentrations of 0.2, 0.5, 0.8 and 1 ppm Hg++. At 24 h, retraction into the shell was observed in 0.8 and 1 ppm Hg++; this retraction increased in these concentrations at 36 h. Retracted snails died if retained in the solutions, but generally recovered within 24 to 48 h if transferred to uncontaminated sea water. Immersionemersion behaviour and interface activity were studied over 24 h by means of an aktograph; snails in normal sea water spent more time below than above the water surface, and exhibited frequent periods of activity. Exposure to mercuric sulphate at concentration of 0.25, 0.5, 0.8 and 1 ppm Hg++ progressively reduced both the length and frequency of activity periods. From 0.5 ppm Hg++ upwards, emersion periods increased, and immersion periods decreased. Oxygen consumption of snails was measured in sea water and in mercuric sulphate at concentrations of 0.2, 0.5, 0.8 and 1 ppm Hg++. Oxygen consumption decreased significantly with each progressive rise in mercury concentration. It is considered that mercury affects M. articulata by interfering with respiration, initially reducing interface activity, then forcing the snail for longer and longer periods out of the water. Retraction occurs when activity is no longer possible. It is concluded that respiratory and behavioural alterations of this nature would afford a good indicator of the presence of sub-lethal concentrations of pollutants.

In the digestive glands of gastropod molluscs, metals are metabolized in the sense that they are subject to inorganic biochemical processes within the epithelial cells and lumen of the digestive tubules and the pore cells in the intervening connective tissue. These systems have been examined in the tower shell Cerithium vulgatum Bruguieres, a sediment feeder, the top shell Monodonta articulata Lam., a grazing herbivore, and in the whelk Murex trunculus L., a carnivore whose prey includes Cerithium . These animals were taken from a Mediterranean environment polluted by heavy metals. In all three species the metals are compartmentalized within mineralized granules as phosphates and within lysosomal residual bodies in association with sulphur. However, the extent to which a particular metal is accumulated and the relative proportions that are bound within the different compartments are factors that are primarily determined by the species and not the concentration available in the environment. Thus Cerithium accumulates high concentrations of a wide range of metals from the ingested sediment and these are rendered insoluble and non-toxic in the digestive gland. This unavailability is transferred to Murex when it eats Cerithium because Murex does not accumulate the full range of metals from its prey. Indeed, for some metals there appears to be bioreduction rather than bioamplification. The grazing herbivore Monodonta articulata accumulates a third distinct spectrum of metals. The accumulations in each species do not reflect the levels of all the metals in the environment. The presence of metals in the digestive glands is associated with the removal of magnesium from the phosphate granules but also with an increase in the concentration of magnesium in the tissue. It is proposed that metals induce the formation of magnesium phosphate as a source of metal-binding phosphate ions.

Shells of the mollusks Cerastoderma (Cerastoderma) edule (Linnaeus 1758) and Monodonta (Osilinus) articulata Lamark 1822 from salt evaporate basins in western Sicily are studied and the effect of environmental conditions (particularly salinity and water chemistry) on mineralogy and chemical composition is investigated and discussed. The elements determined both in seawater and shell carbonate are: Ca, Mg, Mn, Fe, Ni, Co, Cu, Zn, Sr and Pb. Both species studied discriminate against all the minor and trace elements determined; the degree of such discrimination, for some elements, is inversely related to salinity. The mineralogical composition of the shells ( Monodonta has a mixed mineralogy while Cerastoderma is entirely aragonitic) appears to be controlled neither by temperature nor by salinity. In Monodonta shells direct correlations have been found between the following parameters: calcite-Sr (in younger shells only), calcite-Fe, calcite-Pb (in older shells only), calcite-Zn, salinity-Mg and salinity-Pb, whereas inverse correlations were observed between calcite and Sr (in older shells only) and calcite and Pb (in younger shells only). In Cerastoderma shells a direct correlation was found between salinity and Fe and Mg. The thickness of the shells appears, in both species, to be an inverse linear function of salinity.

This widely-spread, and, on the whole, well-marked species, has been in so many cases, as it appears to me, confounded with Alaria bispinosa, that it would be a task of no small difficulty to trace out the mistakes that have arisen in consequence. The imperfect figures of Phillips have, no doubt, been the principal cause of thus confounding the two species. Deslongchamps queried the identification, but yet was inclined to adopt it. Morris and Lycett seem to have had no doubt on the subject. “Having had the advantage of examining a large number of specimens, comprising every variety both in form and stage of growth, we feel no hesitation in uniting the two species here indicated.” It is extremely probable that the Great Oolite specimens of Alaria trifida present varietal differences from the Oxfordian types, and they may also in some cases have assumed forms having only one lateral digitation; but higher up in the Jurassic rocks they seem to be very fairly separable for such a genus as Alaria, which is so prone to effect changes in its shell. Such was doubtless the opinion of Morris, who quotes Al. bispinosa from the Lower Calc. Grit and Kel. Rock, whilst Al. trifida is quoted as a distinct species from the Oxford Clay and Kel. Rock of Yorkshire, the Great Oolite form being referred to a variety.

1. 1. The green pigment in the foot of Monodonta turbinata was isolated. 2. 2. The free pigment was found to be a hydrophilic substance green in acid and yellow in alkaline solution. 3. 3. The absorption spectrum of the pigment in methanolic HCl showed maxima at 680 and 370 mμ (E370/E680=0.87), and inflexions at 440, 330 and 270 mμ. The zinc complex exhibited an absorption maximum at 665–670 mνm, and in inflexion at 615 mμ, after oxidation with iodine. 4. 4. The pigment gave the Gmelin reaction. It did not react with diazotised sulphanilic acid. 5. 5. It is suggested that the pigment is a bilatriene. 6. 6. Green pigment with an identical absorption spectrum was isolated from foot tissue of the realted species Monodonta articulata.

The small freshwater pulmonate Physa has to surface at intervals to replenish its air bubble. If kept in a conical flask with a glass Y-tube giving access to the air above it, an individual snail will tend to go to the same side of the Y with great regularity. Rotation of the maze shows that the snail orients itself with respect to cues within the tube. Further experiments (changing the water in the tube, scrubbing out the tube, swapping tubes between individuals) show that the animals lay trails and follow these in successive runs to the surface; the effect of blocking the ‘preferred’ arm of the Y is reported in some detail. It can be shown that Physa not only responds to the trails laid by other individuals, but is also able to determine the direction in which these individuals were going; the polarized trail lasts about 30 min. Preliminary experiments with the seashore prosobranchs Monodonta and Littorina show that these too lay trails that are followed by subsequent individuals. The phenomenon of snail trailfollowing is discussed in relation to homing and predation, and the interpretation of experiments on learning by gastropods in general.

Five species of marine gastropods (Monodonta turbinata, M. turbiformis, Cerithium scabridum, Littorina punctata and L. neritoides) were exposed to cadmium in the laboratory. The enzyme phosphoglucose isomerase (PGI) tested electrophoretically showed for all five species a statistically significant higher proportion of heterozygotes among the dead animals than among the survivors in the range of concentration tested. This pattern seems to have been established by natural selection. Further, it could be used in developing biological monitors of present and past cadmium pollution based on the genetic response of natural populations to this specific pollutant.

1. 1. Lactate dehydrogenase activities in extracts of a gastropod, Monodonta sagittifera, and a sea urchin, Arbacia lixula, were determined by change in light absorbance of a dye mixture on addition of salts of lactic acid in each isomeric form. 2. 2. The Monodonta extract catalyzed the oxidation of d -lactate only, with an apparent Michaelis constant of 180 mM. 3. 3. Weight-specific enzyme activity of Monodonta was proportional to the −0·18 power of total body weight. 4. 4. The sea urchin appeared to contain two enzymes of equal activity, one specific for l -lactate and one specific for d -lactate.

The species Monodonta (Osilinus) articulata Lamark 1822 is recorded as having a shell with mixed minerals: a calcitic microstructural unit is comprised between 2 aragonitic layers.