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Gastropoda merupakan keong yang bernilai ekonomis tinggi karena cangkangnya diambil sebagai bahan untuk perhiasan dan cinderamata, sedangkan dagingnya merupakan makanan yang lezat. Beberapa jenis keong yang bernilai ekonomis diantaranya dari famili Strombidae, Cypraeidae, Olividae, Conidae, dan Tonnidae. Mempelajari pentingnya manfaat Gastropoda, maka diperlukan adanya kajian tentang hewan tersebut. Oleh karena itu peneliti tertarik untuk melakukan penelitian mengenai hewan Gastropoda yang meliputi jenis dan kelimpahan gastropoda di perairan Kota Bengkulu khususnya di Pantai Teluk Sepang Kota Bengkulu. Penelitian ini menggunakan metode survei dengan menggunakan transek 1x1 meter. Data yang diukur berupa data identifikasi dan data kelimpahan Gastropoda. Berdasarkan hasil penelitian, terdapat sembilan jenis Gastropoda dengan kelimpahan yaitu 216 ind/m2 Cerithidea cingulata, 7 ind/m² Natica gualteriana, 3 ind/m² Trochusconus, 8 ind/m² Turbo chrysostomus, 7 ind/m2 Telescopium telescopium, 9 ind/m2 Strombus labiatus, 162 ind/m2 Cerithidea obtuse, 3 ind/m2 Vexillum rugosum, dan 164 ind/m2 Cerithide aquadrata. Kata kunci: Gastropoda, Pantai Teluk Sepang, identifikasi, Moluska

Genus Natica Scopoli, 1777 Type species. Nerita vitellus Linnaeus, 1758 (subsequent designation by Anton 1838: p. 31). Recent, Indo-Pacific., Published as part of Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, pp. 1-196 in Zootaxa 4654 (1) on page 93, DOI: 10.11646/zootaxa.4654.1.1, http://zenodo.org/record/3365803, {"references":["Scopoli, J. A. (1777) Introductio ad historiam naturalem, sistens genera lapidum, plantarum et animalium, hactenus detecta, characteristibus essentialibus donate, in tribus divisa, subinde ad leges naturae. Apud Wolfgangum Gerle, Prague, viii + 506 pp. https: // doi. org / 10.5962 / bhl. title. 10827","Linnaeus, C. (1758) Systema naturae per Regina tria naturae, secundum Classes, Ordines, Genera, Species, cum characteribus, differentiis, synonymis, locis. Tomus I. 10 th Edition. L. Salvi, Stockholm, 789 pp. https: // doi. org / 10.5962 / bhl. title. 542","Anton, H. E., (1838) Verzeichniss der Conchylien welche sich in der Sammlung von H. E. Anton befinden. Eduard Anton, Halle, xvi + 110 pp. https: // doi. org / 10.5962 / bhl. title. 11509"]}

The Campanian-Lower Paleogene successions exposed at the Kharga Oasis contain well-preserved gastropods. Nineteen gastropod species are identified and described in detail. Two new species are established: Gisortia khargaensis from the lower Eocene El Rufuf Formation and Ornopsis? barisensis from the lower Paleocene Kurkur Formation. In addition to, Turritella (Torquesia) derbesi Coquand is recorded herein for the first time from Egypt. The studied gastropods belonging to four clades: Sorbeoconcha (Metacerithium abictiforme (Wanner), Mesalia hofana Mayer-Eymar, Mesalia sp., Turritella (Torquesia) derbesi Coquand, Turritella (Torquesia) forgemoli Coquand, Turritella kaserensis Hewaidy and Azab, Turritella sp.), Littorinimorpha (Cypraedia bullina Oppenheim, Gisortia khargaensis nov. sp., Natica farafrensis Wanner, Aporrhais schweinfurthi (Quaas), Drepanocheilus bicarinatus Abbass, Drepanocheilus? sp., Anchura? unicarinatus (Abbass), Epitonium sp.), Neogastropoda (Ornopsis? barisensis nov. sp., Rostellana daniensis (Quaas), Vouta sp.), and Heterobranchia (Avellana cretacea Quaas).

article i nfo Drilling predation is one of the unique scenarios where past biotic interactions can be studied quantitatively and used to model behavioural evolution of the involved groups. Although it is recognized that hunger plays an im- portant role indetermining the behaviour of terrestrial predatory groups, its specifi ce ffect on drillinggastropods is largely unexplored. Muricids have been shown to demonstrate change in prey preference and foraging behav- iour when starved. Such behaviour is yet to be tested for naticid gastropods. In an experiment with live naticid gastropods,Natica tigrinaand their bivalve prey Cardium sp., we evaluated the effect of hunger on the following aspects of predation: 1. Drilling frequency, 2. Size selectivity, and 3. Site selec- tivity. Comparing gastropods between satiated controlled group and starved experimental group we demon- strated a positive effect of hunger on drilling frequency. Using different stages of hunger, we found that hunger plays an important role in dictating prey size-selectivity. While hunger increases drilling frequency, it reduces the degree of prey size selectivity. Hunger is not found to initiate edge-drilling or incomplete drilling in N. tigrina. It has been postulated that prey selection by gastropods are correctly modelled by cost-benefi ta nalysis; but the

Geološko podlago njiv in travnikov v okolici Dolenjega Mokrega Polja tvorijo srednjemiocenski (badenijski) laporasti apnenci. Po vsakem oranju teh njiv se na površju zbirajo hišice ter kamena jedra polžev in školjk. Na nekaterih vrstah fosilov smo opazili sledove predacije (izvrtine), zato smo se odločili, da le te podrobneje raziščemo in na podlagi njihove oblike skušamo določiti povzročitelja. Zanimala nas je tudi pogostnost navrtanih lupin. Poudarek raziskave je predvsem na polžjih hišicah turitel. V okviru diplomske naloge sem pregledala dve njivi: prva (lokacija A) meri 20 m2, druga (lokacija B) pa 52,5 m2 . S površine sem sistematično pobrala vse fosilne polžje in školjčne lupine ter njihova kamena jedra. Na lokaciji B sem večjo pozornost namenila pobiranju čim bolj celih hišic turitel, na katerih sem kasneje določevala mesto izvrtin na hišicah. Vrstno sestavo združbe sem določila s primerjavo favne v zbirki Prirodoslovnega muzeja Slovenije. Določila sem 12 različnih vrst, najpogostejša med njimi pa je Turritella turris. Za določanje vrst plenilcev sem izbrane primerke pregledala na vrstičnem elektronskem mikroskopu. Na koncu sem dobljene rezultate primerjala s položajem in obliko izvrtin pri recentnih turitelah. Ugotovila sem, da so bili najpogostejši plenilci turitel naticidni polži, del izvrtin pa pripada tudi muricidam, čeprav fosilnih ostankov le-teh na terenu nisem našla. Najpogosteje je navrtan osrednji del hišice, in sicer med četrtim in sedmim zavojem. Prav tako so tudi recentne turitele večinoma navrtane na osrednjem delu lupine. V primerjavi z recentnimi turitelami so razlike vidne v debelini lupine, v velikosti hišic ter reliefu lupine. Fields and meadows around Dolenje Mokro Polje are underlain by the Middle Miocene (Badenian) marly limestones. After annular plowing of the fields, shells and casts of fossil gastropods and bivalves, originating from these marly limestones, come to the surface. In some specimens are observed traces of predation (boreholes), that were decided to be explored more detail and based on their shape tried to determine the predator. We also documented the abundance of the drilled shells. The focus of the research is on the gastropod Turritella. As part of the diploma thesis, two fields were examined the first (locality A) is 20 m2 large, the second (locality B), measures 52.5 m2. From the area A, all fossil shells and their casts were systematically collected. At the locality B, the emphasis has been on collecting unfragmented (or less fragmented) shells of the gastropod genus Turritella. The species composition of the assemblage was determined by comparison with material stored at the Slovenian Museum of Natural History. Twelve different species were determined, the most common among them is Turritella turris. Some selected specimens were examined to determine the possible predators by observing the boreholes under the Scanning Electron Microscope. Finally, the obtained results were compared with the position and shape of the boreholes in recent Turritella. The most common predators of turritellids are the naticid gastropods, but some borings also belong to muricids, although no fossil muricids have been found at neither of the localities. The most common drilling position is in the central part of the shell, between the fourth and the seventh whorl. Similar, also recent turritellids are mostly drilled in the central part of the shell. Compared with the recent turritellids, there are clear differences in the thickness, size and the relief of the shell.

Cannibalism is observed among the drilling gastropods in Recent and in the fossil record. However, the ecological factors triggering cannibalism are not well understood. While competition over food is considered a factor to initiate cannibalism in certain groups, it is yet to be tested for drilling gastropods. In an experiment with live naticid gastropods, Natica tigrina , we evaluated the effect of the following factors in controlling cannibalism: 1. availability of preferred prey, 2. size ratio of predator and prey, and 3. ontogenetic stage of the predators. Cannibalism is found to be quite rare when preferred bivalve prey ( Cardium sp.) is present. Size ratio among predator and prey is observed to play the most crucial role; cannibalism is maximum in a mixed group of small and large gastropods. While the incidence of cannibalism is much lower in groups of similar body size, the intensity differs with mean size. Cannibalism is relatively common in groups of larger size compared to those of smaller size. This indicates an ontogenetic threshold in cannibalism; the naticids seem to acquire such behavior only at a specific ontogenetic stage. Our findings are corroborated by observed drilling pattern in the Recent shells collected from Chandipur-on-sea, India. While the preferred prey Cardium sp. has the highest drilling frequency, the shells of N. tigrina often bear drill holes; the smaller size class of Natica has the highest drilling frequency among all size classes. The smallest drill holes in Natica are larger than those found in Cardium ; this pattern indicates that the Natica are less likely to attempt a cannibalistic attack in their early ontogeny. These behavioral patterns are also reported from a Miocene assemblage of N. tigrina from Poland (Zlotnik, 2001). It has been postulated that cannibalism should be observed in nutrient depleted conditions. However, our study demonstrates the relative importance of other ecological factors in guiding this behavioral trait. Moreover, the ontogenetic development of cannibalistic habit is closely linked to the evolutionary stable strategy (ESS). Therefore, such factors should also be taken into consideration while studying cannibalism in the context of drilling predation.

The deep-water Naticidae Guilding, 1834 collected in the expedition MD55 off SE Brazil are taxonomically studied; of the eleven species found, nine species and one genus are new. Microlinices n. gen., mainly characterized by its minute shell size (5–8 mm), thick unpigmented shell walls, weak callus, umbilicus wide lacking central fold, corneous operculum, absence of eyes, osphradium somewhat peduncular, penis at right of or ventral to right cephalic tentacle, nerve ring highly concentrated, and found in deepwater environment. The following taxa are studied here: Microlinices latiusculus n. gen., n. sp., the type species, off Rio de Janeiro (RJ), 430–450 m (anatomy included); M. ibitingus n. gen., n. sp., off Espirito Santo (ES) and RJ, 640–1575 m (anatomy included); M. benthovus n. gen., n. sp., same distribution, 607–1575 m (anatomy included); M. ombratus n. gen., n. sp., off ES, 1500–1575 m; M. apiculus n. gen., n. sp., off ES, 367 m; M. gaiophanis n. gen., n. sp., off RJ, 830 m; Natica jukyriu...

Although common, confamilial naticid predation intensity was not very high in the geological record. Here, we gathered modern confamilial predation data from the Indian coasts and showed that confamilial naticid predation on a naticid species, Natica gualteriana, is exceptionally high at Chandipur, one of our studied areas. We studied the different aspects of confamilial predation from the Indian coasts and showed that the predators in Chandipur were highly efficient as evident from high drilling frequency (DF), site stereotypy and low prey effectiveness. Unusually high DF on N. gualteriana may be attributed to its new arrival in Chandipur where it faced competitive elimination through predation by sympatric naticid predators. Reports of failed invasion are rare. Natica gualteriana is a small invader and therefore its invasion success is threatened by resident populations of large species that extensively drill on young individuals of N. gualteriana just to break the bottleneck of their own offspring from...

jukyriuva, Natica Simone, 2014 Natica jukyriuva Simone, 2014: 582 (fig. 9A���E). Gastropoda, Naticidae Paratypes (2 spc): MZSP 105144. Locality: Brazil, Esp��rito Santo, off Ita��nas, 18��59' S, 37��50' W, 295 m depth (type locality), 27 May 1987. Collectors: P. Bouchet, J.H. Leal and B. M��tivier. Preservation: Dry. Remarks: Former MNHN, Paris., Published as part of Cavallari, Daniel C., Dornellas, Ana Paula S. & Simone, Luiz Ricardo L., 2016, Second annotated list of type specimens of molluscs deposited in the Museu de Zoologia da Universidade de S��o Paulo, Brazil, pp. 1-59 in European Journal of Taxonomy 213 on page 33, DOI: 10.5852/ejt.2016.213, http://zenodo.org/record/3840125

pipoca, Natica Simone, 2014 Natica pipoca Simone, 2014: 582���583 (fig. 9F���I). Gastropoda, Naticidae Paratypes (2 spc): MZSP 105144. Locality: Brazil, Esp��rito Santo, off Ita��nas, 18��59' S, 37��50' W, 295 m depth (type locality), 27 May 1987. Collectors: P. Bouchet, J.H. Leal and B. M��tivier. Preservation: Dry. Remarks: Former MNHN, Paris., Published as part of Cavallari, Daniel C., Dornellas, Ana Paula S. & Simone, Luiz Ricardo L., 2016, Second annotated list of type specimens of molluscs deposited in the Museu de Zoologia da Universidade de S��o Paulo, Brazil, pp. 1-59 in European Journal of Taxonomy 213 on page 42, DOI: 10.5852/ejt.2016.213, http://zenodo.org/record/3840125

The larval morphology of the gastropod Cryptonatica janthostoma inhabiting the Northwest Pacific was described for the first time. Hatched planktotrophic veligers of C. janthostoma had shells 250 μm in height with 0.8 whorls, a bilobate velum with a dark brown pigmentation band shaped along its edge, pair of eye spots, tentacles and statocysts. The surface of the embryonal shell (protoconch 1) was covered with fine granules extended at the dorsal side and rounded at lateral surfaces. Concentric crests and growth lines occurred on part of the shell of late free-swimming larvae (protoconch 2) The velum of the C. janthostoma larvae remained bilobate during the pelagic stage of development, whereas it was divided in 4 lobes during larval development in most of the other species of the Naticidae family. The veliger of C. janthostoma was similar to that of Natica montagu from Danish waters [16] by its shape, pigmentation, shell sculpture and velum structure.

Three unknown Littorina species were revealed by allozyme study of snails from the northwestern Pacific. One of them was found in Kasatka Bay (Pacific coast of Iturup Island, south Kurile Islands) together with L. sitkana, which it resembled in anatomical features, but the genetic distance between these species was D = 0.622. The second one was found in Tauiskaya Inlet (northern part of Okhotsk Sea) and was again similar to L. sitkana in morphological and anatomical features, but D = 1.160. The third species was found in Egvekinot Inlet (Anadyrskiy Gulf, Bering Sea) in sympatry with L. natica, to which was close genetically (D = 0.256) although it differed in shell shape.

Summary Growth, productivity and potential for exploitation of the clam Tawera gayi from shallow waters (3–5 m) of Ushuaia Bay, Beagle Channel were investigated. Mean abundance and biomass in the study area were 1091 ± 737 ind. m )2 and 901.83 g SFWM m )2 (shell-free wet mass), respectively. Individual growth was described best by the von Bertalanffy growth model with the parameter values H¥ ¼ 28.03 mm, K ¼ 0.288 year )1 , t0 ¼ )0.34 (r 2 ¼ 0.83). Annual production of the population was estimated to be 120.45 g SFWM m )2 year )1 , corresponding to a production-to-biomass ratio (P/B) of 0.134 year )1 . The single negative exponential mortality model does not fit the population mortality pattern, but predation by gastropods (Xymenopsis muriciformis, Trophon geversianus, Natica sp.) appears to be the major cause of mortality. These highly mobile predators together with the comparatively slow growth and low turnover of T. gayi in Ushuaia Bay limit its potential for sustainable commercial exploitation.

BIOEROSION STRUCTURES ON MARINE MOLLUSCS FROM THE VILLA SORIANO FORMATION (LATE PLEISTOCENE-HOLOCENE) OF URUGUAY. Bioerosion structures found on marine molluscs of the Villa Soriano Formation (late Pleistocene-Holocene) of Uruguay are described, and the main paleoenvironmental parameters dominant during the depositional events are analyzed. The preference of the drilling site on the shell of the prey bivalves by predator gastropods is verified. Three ichnogenera were found: Entobia Bronn, 1838, Caulostrepsis Clarke, 1908 and Oichnus Bromley, 1981. Entobia records the presence of clionid sponges and Caulostrepsis the presence of boring polychaetes. Entobia is also an indicator of clean waters. On the other hand, Oichnus records the predation of gastropods on bivalves and other gastropods. The preferred site of the shell of Ostrea equestris by the predators is the center of the shell, and drills are more common on right valves, due to the life position of this species. Probable species of predators are Urosalpinx cala, U. haneti and Thais haemastoma on hard substrate prey species and Natica isabelleana on soft substrate prey species.

Natica (ss) sp. (an operculum) (Fig. 10C, D) MATERIAL EXAMINED. — Brazil, Espírito Santo: off Itaúnas, 18°59’S, 37°50’W, 295 m, MNHN, 1 operculum (MD55 sta. DC75; coll. Bouchet, Leal & Métivier, 27.V.1987). REMARKS An operculum was collected (14.4 × 8.3 mm), and its analysis shown that it does not belong to anyone of the known species in Brazilian coast and neighborhood. It barely resembles the operculum of Natica ss, as that of N. vitellus (Linnaeus, 1758), the type species of the genus, has an elaborated set of folds in outer edge (Fig. 10C), and is relative smooth in remaining regions. The erosion of its inner surface, which lacks the usual organic matrix that normally covers it (Fig. 10D), shows a certain degree of transportation or long time after death. The relative good preservation allows the deduction that the enigmatic species occurs in the region. Because of the obvious incompleteness of data, a formal description of the species is here considered premature., Published as part of Simone, Luiz Ricardo L., 2014, Taxonomic study on the molluscs collected during the Marion-Dufresne expedition (MD 55) off SE Brazil: the Naticidae (Mollusca: Caenogastropoda), pp. 563-593 in Zoosystema 36 (3) on page 586, DOI: 10.5252/z2014n3a2, http://zenodo.org/record/5159223

Spermatozoa of Natica marochienssish (Gmelin, 1791) is described by light and electron microscopy. The spermatozoon is of the primitive type with head contains a conical acrosomal complex with an acrosomal vesicle of dense matrix having a basis occupied by the subacrosomal space. The middle piece shows the centriolar complex surrounded by mitochondria and the tail contains the axoneme with a 9+2.

The availability of data sets covering more than a year is scarce for tropical environments. Advances in hardware and software speed-up the re-analysis of old data sets and facilitates the identification of hidden data patterns. From February 1984 to April 1987 (49 sampling dates), core samples (17.7cm², 15cm deep) were collected at low tide at a sand-mud flat in the mid upper Gulf of Nicoya estuary, Pacific, Costa Rica. Predator exclusion experiments (cages 0.5x0.5x0.2m, galvanized wire, mesh size 5mm), were conducted at the site in 1985 (dry and rainy seasons sets). Samples were preserved with 5% buffered formalin in sea water stained with Rose Bengal, and washed after 24 hours on a 500 micron mesh sieve. The 1 120 cores yielded a total of 112 morphological species of which the mollusks were represented by 23 species, and included the bivalves Tellina rubescens, Tagelus bourgeoisae, Dosinia dunkeri and Leukoma asperrima, and the gastropods, Natica unifasciata, Nassarius luteostomus, Costoanachis rugosa and Turbonilla sp. The 23 species are indicative of a relatively rich sedimentary molluscan fauna. T. bourgeoisae had a seasonal oscillation, with higher abundancesduring the rainy seasons. T. rubescens was not seasonal, but presented an oscillation with peaks at about 1.5 year intervals. Many empty shells of Cosmioconcha modesta, lower number of N. luteostomus and a few of T. rubescens were found with boreholes by the predatory snail N. unifasciata. T. rubescens was not significantly more abundant inside or outside cages. T. bourgeoisae showed a significant increase within the caged areas. The numerical fluctuations of the mollusks became more important during the rainy season of 1985. Red tide outbreaks in the Gulf of Nicoya in 1985 may have had an impact on the molluscan populations. Rev. Biol. Trop. 59 (3): 1135-1148. Epub 2011 September 01.La disponibilidad de datos con una cobertura mayor al año es rara para ambientes tropicales. Avances en computación y programas de cómputo facilitan el re-análisis de antiguos datos y la identificación de patrones ocultos en ellos. desde febrero de 1984 hasta abril de 1987 (49 fechas de colecta), muestras de barreno (17.7cm², 15cm de profundidad) fueron recolectadas durante la marea baja en una planicie arenosa-fangosa en la región media del estuario del Golfo de Nicoya, Costa Rica. Experimentos de exclusión de depredadores (jaulas 0.5x0.5x0.2m, malla galvanizada, poro de 5mm), fueron realizados en el sitio en 1985 (estación seca vs estación lluviosa). Las muestras fueron preservadas con formalina al 5% en agua de mar teñida con Rosa de Bengala y lavadas después de 24 horas en un tamiz de 500 micras de poro de malla. Los 1 120 barrenos produjeron un total de 112 especie morfológicas, de las cuales los moluscos estuvieron representados por 23 especies que incluyen los bivalvos: Tellina rubescens, Tagelus bourgeoisae, Dosinia dunkeri y Leukoma asperrima, y los gastrópodos, Natica unifasciata, Nassarius luteostomus, Costoanachis rugosa y Turbonilla sp. Las 23 especies son indicadoras de una fauna de moluscos relativamente rica. T. bourgeoisae presentó una oscilación estacional, con mayor abundancia durante la estación de lluvias. T. rubescens no fue estacional, pero presentó una oscilación con máximos a intervalos de cerca de 1.5 años. Muchas conchas vacías de Cosmioconcha modesta, un poco menos de N. luteostomus y unas pocas de T. rubescens fueron encontradas con perforaciones hechas por el depredador N. unifasciata. T. rubescens no fue significativamente más abundande dentro o fuera de las jaulas. T. bourgeoisae mostró una falta de abundancia estacional, pero una densidad significativamente mayor dentro de las jaulas. Las fluctuaciones poblacionales de los moluscos fueron más importantes durante la estación de lluvias cuando se les compara con las fluctuaciones de los poliquetos, crustáceos y otros grupos. Mareas rojas en el Golfo de Nicoya durante 1985 podrían haber tenido un impacto en la dinámica de las poblaciones de moluscos.

The excretion kinetics of110mAg in a gastropod species contaminated through water pathway has been studied under laboratory condition. The pattern of the excretion results can be represented by a monophasic linear regression function. The excretion coefficient and biological half-life were calculated. The biological half-life was found to be 33 days. The study suggests that the excretion rate of110mAg byN. intricata may be considered as a potential biomonitor on the shoreline of the Black Sea marine environment.

Quintana Roo tiene mas de 500 especies de gasterópodos pero muy poco se conoce de los estadios larvales. Muestreamos cuatro sitios mensualmente de enero a diciembre de 2008 con arrastres de plancton por triplicado y con una red cónica con malla de 300μm. Puerto Morelos tuvo los mayores registros (41.26±63.23 larvas•10m-3), seguido por Mahahual (14.78±28.21 larvas•10m-3), Sian Ka’an y Xel-Há presentaron las densidades menores (9.16±16.73 y 3.35±4.33 larvas•10m-3, respectivamente). Mayo y agosto presentaron los mayores registros (33.66±67.39 y 31.78±25.92 larvas•10m-3, respectivamente), marzo y diciembre los menores (1.70±1.88 y 3.18±5.27 larvas•10 m-3 respectivamente). Se registraron diferencias significativas en la densidad media espacial (p

Mollusk association patterns can provide good ecological indications in coastal ecosystems. The subtidal marine environment from Gravata to Porto Belo Island in Santa Catarina state/Brazil, was sampled from September 2001 to August 2002. Sediment was sampled in this area with a van-veen grab (0,025 m2 of sampling area) at 10 to 12 meter depths (Gravata to Laranjeiras). At Porto Belo Island samples were taken by scuba diving with one core that sampled an area of 0,018 m2. At least five samples were collected in each station. Samples were washed in 0,5 mm mesh size sieves and fixed with 10% formalin. Similarities between samples were calculated by Jaccard coefficient. Over the similarity matrix cluster analysis were applied using the UPGMA method to form the groups. Correspondence analysis was applied to identify the mollusk association. Forty two benthic taxa were identified: 1 Polyplacophora, 7 Gastropoda and 34 Pelecypoda. Most frequent mollusks were Tellina spp., Natica livida and Abra sp. Two assemblages were identified: one encompassed the area between Gravata to Laranjeira and the other characteristic of the Porto Belo Island.

M. Griffin (Division Paleozoologia Invertebrados, Museo de la Plata, Argentin) and P. Bouchet (Muséum national d'Histoire naturelle, Paris) have kindly brought to my attention the fact that the genus name Taniella Kase (1990, p. 573; type species Taniella japonica Kase, 1990) is preoccupied by Taniella Finlay and Marwick, 1937, p. 48 (type species Natica notocenica Finlay, 1924). Consequently, a new name, Tanimasanoria, is proposed as a replacement for Taniella Kase, 1990. It is named in honor of Masanori Tani, for years of collecting the Izumi gastropods.

The cercaria of Stephanostomum caducum (Looss 1901) Manter 1934, develops in redia in the marine prosobranch Natica alderi. The ocelate cercaria has two alternating rows of oral spines and a stylet. The distal part of the tail is able to invaginate and function as a sucker. The cercaria is probably identical with Cercaria obtusicaudata Pelseneer 1906. The cercariae encyst below the epidermis of the mouth of fish belonging to the family Gobiidae. The nietacercariae have 24 or 25 oral spines in each of the two rows. S. caducum developed in the pyloric caeca of cods fed on experimentally infected gobies. Cod, Gadus morhua, is the natural final host for S. caducum in Danish waters. The different developmental stages were studied using the scanning electron microscope.

Dynamics in three deep-water populations, one northern and one southern at 100 m and one at 300 m, of the surface deposit-feeding bivalve Abra nitida (Muller) were studied during the period 1970–1980. Recruitment, growth in terms of length, mortality, and production of biomass were assessed by means of length frequency distribution analysis of quantitative samples. Recruitment success in different years was negatively correlated with adult density/population biomass at two of the localities, 100 and 300 m deep. The mortality of the 0-group was positively correlated with the size/density of the 0-group itself. Mortality among adults was considerably higher at 100 m, and for the southern 100 m population data are presented indicating a negative relationship between Abra and the predatory snail Natica. The average growth rates were considerably higher at 100 m compared with 300 m, which is attributed to a better food supply rather than higher temperature. Growth rates were negatively correlated with adult density/biomass at the two stations where Abra dominated. Production of biomass (shells included) was calculated for 9 consecutive yr at the southern 100 m station, and for 4 yr at 300 m. P ranged from 9.94 to 37.85 g dry wt· m−2 /sd yr−1 and P : B ratios from 0.54 to 1.46 at the former site, and the corresponding values from the latter site were 0.57–2.62 and 0.46–2.5. The production on the former site was high for a “deep” community. It was concluded that normally the factors regulating the Abra populations operated on the bottom rather than during the planktonic phase. The results strongly indicated that resource limitation on the bottom is a factor of prime importance in regulating the deepest (300 m) population, primarily acting through adult-larval interactions, while predation probably plays a greater role at 100 m. At the southern 100 m site where Abra may occasionally reach an adult density of 2000 ind. · m−2, both predation and resource limitation affected the dynamics of the species. Reasons for the “volatility” shown by the species are discussed, whereby a good competitive ability together with high susceptibility to predation are considered to be important. The findings demonstrate the importance of density-dependent factors in regulating these deep-water depositfeeding populations.

We determined causes of predation on an early Pleistocene assemblage of ten species of Naticidae in Fiji. Naticids preyed more frequently on the four Natica species (27% of shells drilled) than on Polinices, Eunaticina and Sinum (3% of shells drilled). Tertiary and Cretaceous naticids studied previously are generally less frequently drilled. The absence of incomplete boreholes indicates that drilling predation is typically successful. Predator size (based on borehole diameter) increased directly with prey size in all Natica species. Incidence of drilling predation decreased slightly with increasing prey shell size, but Natica species do not appear able to outgrow drilling predation. Unsuccessful crustacean predation, indicated by scar lines and shell repair, occurred frequently. In the eight commonest naticid species, 17–48% of the shells had healed fractures. The results identify two trophic links in the fossil community, naticids as generally successful predators and crustaceans as often unsuccessful predators, both on naticid prey.

Natica gualteriana, as observed on intertidal sand bars in Bantayan Island, Philippines, emerges from the sand at low tide when the bottom is exposed to the air, and hunts epifaunally for the trochacean gastropod Umbonium vestiarium. N. gualteriana captures U. vestiarium with a quick extension of the foot, triggered by direct contact with the prey. The shell aperture of the prey is subsequently plugged with a small amount of mucus, that forces U. vestiarium to remain retracted inside its shelf (chemically benumbed?), but neither kills nor permanently affects it. Drilling of the prey takes place infaunally, after burrowing. This seems to be the first record of subaerial hunting in naticid gastropods.

Boreholes produced by naticids and muricids can be recognized in molluscan prey from the Ameki Formation (Eocene) in southeastern Nigeria. Possible predators are four species of Naticacea and three species of Muricacea. A quantitative assessment of the occurrence and type (naticids or muricids) of borings in 1409 fossil shells belonging to seventeen species shows that there is a pronounced differential proneness to attack among the species. The most common prey species of naticids were the infaunal, feebly ornamented bivalve Tivelina newtoni and the infaunal, smooth gastropod Natica amekiensis. The principal prey of muricids was the epifaunal, strongly ornamented gastropod Bonellitia (A.) amekiensis.

Seven previously described and seven new taxa of gyrodiform naticoids from West Coast Late Cretaceous–Paleocene age strata are discussed. Gyrodes (Gyrodes) dowelli White of Turonian age is a typical Gyrodes; G. robustus Waring from the Paleocene has the shape of Gyrodes s.s. but lacks the crenulations. G. greeni Murphy and Rodda, G. yolensis n. sp., G. quercus n. sp., G. banites n. sp., G. canadensis Whiteaves, G. pacificus n. sp., and G. expansus Gabb comprise the new subgenus Sohlella, which thus ranges from Cenomanian through Maastrichtian. Gyrodes robsauli n. sp. resembles “Polinices” (Hypterita) helicoides (Gray), and Hypterita is reassigned to the Gyrodinae as a subgenus of Gyrodes. Gyrodes onensis n. sp. of Albian age is similar to the G. americanus group of Sohl (1960). Three texa—Natica allisoni (Murphy and Rodda) of Cenomanian age and N. conradiana Gabb and N. conradiana vacculae n. subsp. of Turonian age—which have all been previously considered to be Gyrodes are placed in Natica. Well marked relict color patterns on N. conradiana and N. conradiana vacculae suggest that these naticids from northern California and southern British Columbia were tropical forms.Diversity of taxa and size of specimens are reduced at the end of the Turonian, suggesting a change in West Coast marine conditions at that time.

Oxygen consumption in sea water increased with size and tissue weight of Natica maculosa Lamarck at ambient temperatures (28–29.5 dgC) and salinities (31–32‰) in a fashion comparable with other naticids. When measured in submerged shore sand, oxygen consumption resembled that in sea water among smaller and some larger Natica but was much lower in several larger snails. Even using the higher measurements, respiration accounted for a remarkably low proportion of the energy consumed in Umbonium prey, and this also matches previous findings with Polinices. Limited observations indicate that production of egg collars may account for > 30‰ of the consumption in adult females. Estimation of faeces and mucus were, however, unsuccessful. It is suggested that respiration in nature might be higher than recorded hitherto because of high metabolic costs and very long duration of drilling the shelled prey.

The responses of the gastropods Natica josephina , N. millepunctata and N. hebraea to the touch or near presence of 10 Mediterranean sea stars were studied. In all but two cases a positive response consisted either in more or less complete podial responses, i.e. a covering of the shell by podial folds, and/or movement away from the sea star. Natica millepunctata, however, responded to Astropecten aurantiacus and A. irregularis by extending its proboscis and rasping off spines and tube feet of which the latter were engulfed.

The stomach contents of 124 Astropecten articulatus have been identified and discussed. This starfish ingests great numbers of small sand-dwelling organisms. Ninety-one species of invertebrates were recovered, of which 73 were molluscs. The gastropods Acteocina candei, Natica pusilla and Olivella mutica comprised over 60% of the animals recovered. Astropecten articulatus apparently ingests whatever animals or shells it encounters. Because it effectively samples tiue fauna of offshore sand bottoms, its use is recommended as a collection tool for the study of this community.

The distribution of Trypetesa lampas (Hanoock) and its rates of infection of different species of gastropod shells in the waters of Anglesey were studied. T. lampas was found in depths from 3 to at least 25 fathoms (5 to 46 m). It infected dead shells, mainly of Buccinum undatum L., Colus gracilis (da Costa), Neptunea antiqua (L.) and Natica alderi (Forbes); it was absent from shells occupied by hermit crabs in the intertidal zone. Significantly more B. undatum shells were infected than shells of N. antiqua and Natica alderi, and more of both C. gracilis and N. antiqua than of Natica alderi. Larger shells of B. undatum were more likely to be infected than were the smaller ones. The number of females per shell varied with the shell length raised to the power 2.39 instead of as expected with the square of the length.

General Conclusions The Eocene molluscan faunas of Trinidad show no near alliances with any other known faunas. In this they differ from the well-known and easily recognized Miocene fauna found in Haiti, Jamaica, Cuba, Cumana, Trinidad (Caroni Series), and other localities. Nevertheless a few of the forms have been found elsewhere. The Echinolampas ovumserpentis, Terebratula carneoides , and Ranina porifera of the Naparima Beds recur in the Eocene of St. Bartholomew9s (north-eastern West Indies), and I have already noted that the same beds have a Nucula and a Leda in common with Barbados. It is only with doubt that the name of Natica phasianelloides , a Miocene fossil of Cuba and Jamaica, can be assigned, to the imperfect casts found near San Fernando in Trinidad. Of these casts some are fully 6 inches long. Some Pinna -like shells, also in the state of casts, found in these beds are still larger than this. Erycina tensa , a near ally of E. obliqua , Caillat, of the Paris Eocene, was described by me from the Manzanilla Beds in Trinidad. Gabb included the name in his list of the Miocene fossils of Haiti. When dealing with the fossils of that island I passed over this observation, but I have since seen reason to believes, that Gabb9s shell was not Erycina tensa , but the flatter valve of a species of Corbula . These corrections leave us with a single molluscan species ( Corbula vieta ) in common between the Eocene and the Miocene of the West Indies. The foraminifera of the shallow-water

1. It is shown that Crepidula fornicata and Natica cataena are capable of synthesizing sterols from acetate and mevalonate respectively. 2. In this investigation N. cataena did not synthesize sterols from acetate. This phenomenon is discussed. 3. It is supposed that all Mesogastropoda possess the capacity of synthesizing sterols. 4. The composition of the sterol mixtures of C. fornicata and N. cataena is determined by means of gas-liquid chromatography. 5. These sterol compositions are compared with those of other mesogastropods.

The Corals of the Miocene formations of the West Indies having been made known by, the researches of Mr. Lonsdale and Dr. Duncan, the Shells having been in part described by Messrs. Carrick, Moore, and Sowerby, and a notice of the Foraminifera having been given by Professor Rupert Jones, I propose to bring under the notice of the Geological Society the Echinoderms belonging to the same fauna. The Echinoderms about to be noticed are found in the island of Anguilla, and in Trinidad, associated with remains which leave little doubt of their Miocene age. Two of them are identical with Maltese species, and three more are found living in the West Indian seas, Three others seem to be new, and I have therefore appended descriptions of them. In Anguilla the fossil Echinoderms occur in a white marly limestone, in which are found numerous remains of mollusca, chiefly as casts. Several of the mollusca are identical with species found in San Domingo, Jamaica, and other West Indian Miocene localities. The most noteworthy are Natica phasianelloides , d9Orb., Solarium quadriseriatum , Sow., and species of Turritella and Pecten . Teeth of Pycnodont fishes also occur in the beds, as in Malta, and among them is one apparently very closely allied to Sphœrodus gigas . Several of the other mollusca are probably identical with those of the West Indian localities mentioned; but it would be hazardous to speak precisely, where the only materials are imperfect casts. In Trinidad the fossil Echinoderms are found in highly inclined gypseous

NATICA or the naticoici type holds a unique place in the ontogeny and phylogeny of the coiled Gastropoda. Its position in the history of the race has been admirably pointed out by Grabau1 in his " Studies of Gastropocla," and in his treatise on the "Phylogeny of Fusus and Its Allies. "9 There would be little cause at this time to take up the discussion again, if it were not for the fact that certain new data pertaining to the development of some Paleozoic, Mesozoic, Cenozoic and Recent forms have been observed. The basis for classification as presented by Dall,3 iUlrich,' Grabau5 and others will probably always be argued pro and con, depending upon the point of view of the zoological systemiatist at the time he makes a study of the living forms. His material for study consists or should consist of the entire living organismi; consequently he is able to trace the ontogeny of an individual in detail. But, to the paleontologist, who is dependent upon the shell of the fossil gastropod for his study, the emphasis is placed on the shell development as a means of formulating a natural classification. The fundamental law governing the development of races was briefly stated by Alpheus Hyatt, "Ontogeny recapitulates phylogeny. " This, to Hyatt, was not a new concept, for Louis Agassiz, in 1847, stated, "The Lord brings back in the young those types that have gone be

On a sandy beach of the Dutch North Sea coast an experiment was carried out with 24000 brightly coloured artificial shell valves of Donax vittatus . Unperforated and perforated (artificial Natica -holes of 1, 2 or 3 mm inner diameter) left and right valves of three sizes (19.7, 24.2, and 28.7 mm shell-length) were used. It appeared that under the influence of waves and water currents a clear selection occurred according to size (“ size effect ”), symmetry (“ left-right phenomenon ”), presence or absence of a hole (“ hole effect ”), and diameter of the hole (“ diameter effect ”). The implication of these observations for studies of the biology of Naticid snails based upon valves collected along the beach are discussed. Furthermore, some remarks are made on the implications of this type of experimental work for sedimentology and marine palaeontology in general.

These fossils are especially interesting on account of their having been obtained from a more southerly point than any hitherto recorded. The number of specimens is nine; five of these are referable to the genus Cucullœa, one to Cytherea, one probably to Natica, and two are fragments of Coniferous Wood. With the Cytherea are other small shells which may indicate the presence of Crassatella (?) and Donax (?). Two of the pieces of Cucullœa are entirely free from matrix, while three show in their interiors a fine sandy rock which effervesces when treated with hydrochloric acid. The shells themselves have a calcedonic appearance, but, like the matrix, they effervesce strongly with acid; they are much denuded, having apparently been long exposed to the weather. The matrix within the Cytherea is coarser than that in the Cucullœa, containing, besides fragments of quartz and of a black rock, numerous fragments of shells. The Natica (?) is almost free from matrix, and is much denuded, but in some of the crevices sandy material may be seen very like the matrix of the other shells. All these genera have a wide distribution in time, and are now living, consequently they give but little clue to the age of the rocks in which they were found. Cucullœa is rare at the present day, and the few known species occur in the Mauritius, Nicobar, and China; but as a fossil it is very common and widely distributed.

A definitive systematics of the Neogene European Naticidae has not yet been compiled. There remainsome problematic species which have been subject to controversy for a long time. Most of them are composed of forms with similar teleoconchs but different protoconchs. The differences in the protoconchs are significant enough because they involve different types of larval development. Thus, these forms could be considered as distinct species. In this paper we analyze the case of Natica strictiumbilicata Sacco ,, a species from the Mediterranean Pliocene which has hitherto been confused with Natica pseudoepiglottina Lamarck .. The main characters that allow us to state that N. strictiumbilicata is a singular species are the number of whorls of the protoconch, the nucleus diameter and the maximum diameter of the protoconch. We propose the protoconch as a useful tool for systematics of Naticidae. Finally, some paleobiological and paleobiogeographical considerations are discussed.

SANDY-BEACH gastropods of the family Naticidae and of the genus Bullia (family Nassariidae) are capable of a remarkable expansion of the foot. So great is this expansion that it has often been suggested that the turgor of the foot is not due to haemolymph alone but also to water from the surrounding medium which is supposedly introduced into the foot during expansion and expelled during contraction. Schiemenz1,2 attempted to show such a mechanism in Natica and claimed to have demonstrated the existence of pores opening into an “aquiferous system” which was completely separate from the blood sinuses. Though these findings were accepted by a number of workers, including Gilchrist3, they have never been corroborated, and most subsequent authors have assumed, as did Pelseneer4, that the volume of haemolymph is quite adequate for expansion of the foot in all gastropods. Nevertheless, a small body of opinion has tended to the view that in certain marine gastropods expansion of the foot may be brought about partly by the introduction of sea-water. Morris5, working on Uber, has tried to resolve the controversy by measuring the volume of fluid given off when the animal retracts and comparing it with the volume of water contained in the “free space” and elsewhere when the animal is expanded. Her results are unfortunately inconclusive and her observation that the expelled fluid often contains “blood-corpuscles” adds a complication to the problem.

THE study of quantitative collections of dead shells belonging to the lamellibranch Mactra stultorum Linne, for the year classes of 1952–1957 on the Dogger Bank, is yielding valuable information on the mortalities exerted by several classes of predators. The chief ones which are recognizable from the dead shells are the drilling prosobranch Natica poliana Forbes and the asteroids Asterias rubens Linne and Astropecten irregularis (Pennant). The prosobranch drills a hole through the shell and presumably feeds through this hole; the actual method of its feeding has not been described although its method of drilling has received considerable attention. Turner1 lists a full bibliography on the drilling mechanism. Very occasionally, live Mactra are caught, and more rarely, their dead shells, bearing an incompletely pierced bore-hole. It is presumed that the Natica was interrupted in its meal through itself being attacked by a larger predator. Even more interesting are some very rare instances of Mactra having sealed over the incomplete bore-holes on the inside, with an outgrowth of the nacreous layer. We have noticed such seals in both living and dead (at the time of collection) bivalves, in individuals ranging from 4 to 31 mm. Fig. 1 shows a typical sealed bore-hole. The area covered by the seal is very much larger than the bore-hole itself; this may be explained by the fact that, as has been observed, sand enters through the bore-hole and irritates a large area of the mantle membrane. Wasteful killing of very young Mactra by very young Natica seems to be indicated by shells which bear up to five bore-holes and still contain flesh.

The ability of marine prosobranchs (Nucella, Ocinebra, Natica) to drill holes in the shells of other mollusca, afterwards introducing their proboscis to suck out the soft parts of their victims, has been known by man during the past two thousand or so years1. Nevertheless, it has still not been decided whether this drilling takes place by mechanical means only or whether a secretion of acid from the pharynx, the salivary glands or (in the Naticidae) from the so-called boring gland takes part in the process. Schiemenz2, Hirsch3, Boettger4, and Ankel5,6 are all of opinion that secretion is active during drilling, whereas Fischer7 and Pelseneer8 feel convinced that drilling is carried out with the radula, that is, by mechanical means only.