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Imbricata-type cercariae from Hydrobia salsa, a brackish-water, prosobranch snail taken near Woods Hole, Massachusetts, emerge shortly before noon, are photopositive and encyst after swimming for a few minutes to three to four hours. Metacercariae were fed to chicks and domestic ducklings and developed to mature worms after about two weeks in the bursae Fabricii of these birds. Adult and larval stages are described and figured. The worms belong in the family Notocotylidae and are assigned to the genus, Uniserialis Beverley-Burton, 1958. Systematic problems of genera in the family are discussed.

Distomum vibex was described by Linton (1900) from Spheroides maculatus at Woods Hole, Massachusetts; the species was named type of a new genus, Lintonium, by Stunkard and Nigrelli (1930). Sporocysts and cercariae were described and the life-cycle was postulated by Martin (1945); further detailed descriptions of the sporocysts and cercariae were provided by Cable (1954), and a report of the life-cycle is given in the present paper. Other species, assigned to the genus Lintonium, have been described from the Sea of Japan, the South China Sea, Tasmania, Australia, Ceylon, the Bay of Bengal, West Pakistan, Hawaii, and the Gulf of California on the west Coast of Mexico. Published accounts are reviewed, but possible influence of development in different hosts can not be assessed with confidence and criteria for specific determination are uncertain. When information on life-cycles and intermediate hosts becomes available, taxonomic decisions can be made with more assurance.

Metacestoid stages of tetraphyllidean and tetrarhynchidean cestodes were described from marine fishes by O. F. Mueller (1787), Fabricius (1794), and Cuvier (1817). Although known for more than a century, knowledge of these tapeworms is meager, and the life-cycle has not been experimentally demonstrated for any one of them. The worms mature only in the spiral valve of elasmobranch fishes, but larval and developmental stages occur in a great variety of marine invertebrates as well as in fishes. Technical difficulties of maintaining experimental hosts for long periods under controlled laboratory conditions have precluded the successful completion of life-histories. After a period of incubation, the eggs contain motile larvae, oncospheres, which, when eaten by copepods, migrate to the body cavity and transform into second stage larvae, procercoids. When the copepodes are eaten, the procercoids emerge from the intestine of the second intermediate host and enter the body cavity or penetrate adjacent tissues whe...

Linton (1910) described Dinurus rubeus n. sp., a digenetic trematode from species of Lycodontis at Tortugas, Florida, and Manter (1931) described a second species, Dinurus magnus, from Synodus foetens at Beaufort, North Carolina. He (1947) transferred both species to the genus Stomachicola Yamaguti, 1934, as Stomachicola rubea and Stomachicola magna. Meanwhile, Linton (1940) described Dinurus pinguis from Menidia menidia at Woods Hole, Massachusetts, and Manter (1947) transferred this species, pinguis, to Tubulovesicula Yamaguti, 1934. Sinclair et al. (1972) in a 2-year study of Stomachicola rubea noted that the worms attain maximum size only in the stomach of "true" definitive hosts, large fishes, and that small fishes, which ingest planktonic invertebrates, serve as "transfer hosts." In these hosts, the parasites may wander about in the tissues, or may be encysted. These authors predicated that T. pinguis is, in such a transfer host, a stage in the life cycle of S. rubea. Stunkard (1973) described the d...

A survey of published descriptions of bucephalid trematodes provides bits of information on definitive and intermediate hosts, life histories, developmental stages and systematic relations. Adults live in the digestive tracts of marine and freshwater fishes; miracidial larvae emerge from the eggs and enter bivalve mollusks, where they give rise to branched sporocysts in which fork-tailed larvae are produced. These larvae, described by von Baer (1827), invade small fishes, where they encyst; when ingested by definitive hosts, they become sexually mature, completing the cycle. Although outlines of the life history are clear, correlation between larval and adult stages is known for only two marine and four freshwater species. Lack of information on successive stages of particular species has led to confusion in systematic and taxonomic determinations. The relative significance of different morphological and developmental features, especially of the excretory system, is controversial. A new genus, Rudolphinus, is erected to contain Prosorhynchus crucibulum (Rudolphi, 1819) Odhner, 1905, since the species is not congeneric with Prosorhynchus squamatus Odhner, 1905, type of the genus.

A survey of the marine cercariae of the Woods Hole, Massachusetts region was made by Stunkard (1970). That report was concerned with fifteen families and thirty two species of digenetic trematodes. Their morphology, definitive and intermediate hosts, and systematic relations were considered. It was noted that the first inter mediate host, the molluscan, is more specific than the definitive vertebrate host and that the second intermediate host, when present, may be a mere paratenic or trans port host. In it, the metacercariae may encyst, or not, may fail to develop, or grow to almost full size and attain sexual maturity, a condition known as progenesis. The evolution of life-histories in the Digenea was discussed by Stunkard (1957a, 1959, 1975). Ecological relations and environmental conditions are more complex and diverse for marine trematodes than for terrestrial and freshwater species. The mainte nance and experimental infection of intermediate and definitive hosts entail more difficulties with marine than with freshwater forms. Accordingly, the elucidation of life-histories of marine digenetic trematodes has not been a favored line of research. The description and naming of the sexually mature form of a species is a useful and praiseworthy task, but until the larval and developmental stages are known, the specific description is incomplete and may be faulty. For definitive classification and the determination of phylogenetic relations, it is essential that information of the complete life-history be available.

Cercaria adranocerca n. sp. was described by Stunkard and Uzmann (1959) from the clam Gemma gemma at Boothbay Harbor, Maine. Further study of the species at Woods Hole, Massachusetts, has afforded information for revision and correction of the original description. The cercariae are microcercous and after emergence from their sporocysts are encysted in the haemocoele of the clam. They may be extruded, either singly or embedded in a jelly-like matrix, and float in seawater. Feeding metacercariae to Menidia menidia yielded developmental stages to mature worms, identified as Lasiotocus minutus (Manter, 1931) Thomas, 1959. Discovery of the life cycle may aid in resolution of the controversy concerning the status of the genera Lasiotocus Looss, 1907; Genolopa Linton, 1910; and Proctotrema Odhner, 1911.

Digenetic trematodes from the white perch, Morone americana, were identified by Linton (1900) as Distomum areolatum Rudolphi, 1809. He (1901) referred specimens from the cunner, Tautogolabrus adspersus, and the winter flounder, Pseudopleuronectes americanus, to the same species. These worms were collected at Woods Hole, Massachusetts. Other specimens were taken from Bairdiella chrysura, Micropogon undulatus, Orthopristis chrysopterus, and Sciaaenops ocellatus at Beaufort, North Carolina. Linton (1940) included all these worms in a new species, Lepocreadium trullaforme. But they are not specifically identical with L. trullaforme and their taxonomic status has been uncertain. The metacercariae of these worms have been known for many years an unencysted distomes in the ctenophores and medusae taken in plankton collections. The discovery of an ophthalmotrichocercous cercaria from Nassarius trivittatus with the same morphology, has led to the completion of the life-cycle and the resolution of the taxonomic sta...

The genus Odlineria was erected by Travassos ( 1921 ) to receive a new species, designated Odhneria odhneri, from ti-ic yellow-crowned night-heron, Nyctanassa violacea, taken iii Manguihos (Rio), Brazil. Ti-ic genus was included originally in ti-ic subfamily Brachycocliinae Looss, 1899, family Brachycoeiiidae Johnston, 1912, which contains parasites of cold-blooded hosts. Yamaguti (1958) noted the agree ment between Odhncria and members of ti-ic subfamily Maritrematinac Nicoll, 1909, family Microphalhidae Travassos, 1920, which contains chiefly parasites of birds. Accordingly, he transferred Odhneria to Maritretnatinac. This disposition was accepted and 0. odhneri was redescribed briefly by Travassos, Teixeira dc Frcitas, and Kohn (1969). Sinclair ( 1971) next reported 0. odhneri front 14 species of shorebirds, eight taken in the region of Woods Hole, Massachusetts and six at Sapelo Island, Georgia. The discovery of cncystcd metacercariae in timeabdominal muscle of the common prawn, Palaemonctes vulgaris, from Quissett harbor near Woods Hole, initiated the investigation. Incidence of infection in the shrimps was heavy, about 75% of those taken were parasitized, and as many as 90 cysts were found in a single individual. The older, larger specimens were most heavily infected at-id ti-ic young, half-grown ones had few or no cysts. In a shrimp, ti-ic cysts were of varying sizes, (Figs. 3, 8), forming a continuous series from-i-iminute ones, 0.014 by 0.017 mm, to mature cysts 0.34 mn-i in diameter. The size differences signified repeated reinfection over a long period of time, and suggested that the snail-host was shedding cercariac during much of the year. Large cysts are enclosed in a weak, fibrous capsule, deposited by ti-ic host. Ti-ic cyst wall is composed of two layers, equal in thickness, each measuring 0.020 to 0.030 mm. TI-ic large cysts, (Figs. 4, 9) arc clear, translucent, hard, tough, and bounce like marbles. When left for 48 hr in half-tap-half-seawater at 38°C., the wall is weakened and easily ruptured. Under covcrglass pressure, the n-ictaccrcariae escape. Ti-ic worms (Fig. 5) almost complete their growth in the cyst. Their morphology clearly marks tl-iem as microphalhid parasites of an avian or mammalian host. About 50 large cysts were fed to a white mouse and 10 excysted worn-is were recovered from ti-ic rectum 36 hr later. They were active, but free in lumen, in the midst of fecal material, and clearly on ti-ic way to elimination. There was no

The morphology, composition and distribution of the genus Stephanostomum are considered. Taxonomic uncertainties and difficulties are discussed. It is postulated that the difficulties can be resolved only with knowledge of life-cycles, larval forms, and developmental stages. Previous accounts of life-histories in the genus are reviewed. The cercariae described by Miller and Northup (1926) from Nassa obsoleta at Woods Hole are listed and their life-cycles are traced. Cercaria dipterocerca Miller and Northup, 1926 penetrated and encysted in laboratory-reared specimens of Menidia menidia. They continued their development and the mature metacercariae manifest such precise agreement in number and shape of peristomial spines and in general morphology with juvenile and mature specimens of Stephanostomum dentatum (Linton, 1900) Manter, 1931, that C. dipterocerca may be the larval stage of S. dentatum. Cercaria dipterocerca is very different, however, from the cercariae described by Martin (1939) and Wolfgang (195...

Encysted metacercaniae of Zoogonus are reported from the seaurchin, Psammechinus miliaris, at Wimereux, France. Comparison with descriptions of other larval Stages found at Roscoff and Marseilles indicates that all belong to the same species. Attempts to infect sea-urchins at Woods Hole with the American form of Zoogonus were only partially successful. Bionomic and morphological differences between the European and American representatives of Zoogonus are discussed. It appears probable that they belong to different species.

Recent publications present diverse opinions concerning the classification and taxonmy of the Trematoda. Dollfus (1958b) adopted the system of Faust and Tang (1936), recognizing three subclases: Monogenea, Digenea, and Aspidogastrea. Baer and Euzet (1961) removed the Monogenea from the Trematoda and regarded the group as a separate and independent class in the phylum Platyhelminthes, while Baer and Joyeux (1961) restricted the Trematoda to three subclases: Aspidogastrea, Digenea, and Didymozoidea. Stunkard (1962) presented a new arrangement and restored the terminology of Burmeister (1856) but revised the status of the Aspidobothrea. The class Trematoda was divided into two subclasses, Pectobothridia and Malacobothridia. The Pectobothridia contain two orders, Monopisthocotylea and Polyopisthocotylea; the Malacobothridia contain two orders, Aspidodothrea and Digenea. Morphological and development data are presented to support the opinion that the polystomes should be retained in the Trematoda; that the Did...

Summary The purpose and objective of classification is to portray genetic relations by taxonomic symbols. Adoption by trematodes of a parasitic mode of life has induced changes in nutrition, physiology, morphology, life cycles and development. These adaptive modifications have resulted in both convergent and divergent evolution. Criteria for determining genetic relations must be assessed with caution and no single measure can be accepted as reliable or adequate. Although certain features appear to be correlated, they may have developed independently and the evaluation and interpretation of diagnostic characters is very difficult. Types of adhesive organs and the extent of their development may be associated with the site of infection, but life histories and the type of development afford more significant information concerning genetic relations. Consideration of morphological and developmental data lead to the conviction that in the Digenea, the higher taxonomic units have little phylo-genetic or systematic significance. It is proposed therefore, to suppress the orders Gasterostomata and Proso-stomata, and in the latter the suborders, Amphistomata, Distomata, Monostomata, Strigeata, Bucephalata, Schisto-somata and Clinostomata. Although superfamily groups may be recognized, their limits and interrelations are not yet clearly defined and their erection should await more complete information. Former systems for classification of adults were based on morphological features, some of which have proved unreliable, and life-history data are yet too meagre for final evaluation and application. Classifications of larval stages, based on types of asexual generations or on larval structures such as form of tails, presence of stylets, etc., have proved more unsound than classifications of adults. Only an analysis, evaluation and correlation of all data can produce a truly natural system. Such a system must be based on and portray the evolutionary history of the trematodes. Phylogenetic considerations are reviewed and applied to taxonomic problems.

The successive stages in the life-history of Homalometron pallidum, a parasite of Fundulus heteroclitus, described by Linton, 1901 and named by Stafford, 1904 have been discovered and identified. The asexual generations are in Hydrobia minuta and the metacercarial stages are encysted in Gemma gemma, H. minuta, and small polychaete annelids which serve as secondary intermediate and transfer hosts. Knowledge of larval as well as adult stages gives a better basis for determination of the evolution and systematics of the allocreadiid-leprocreadiid trematodes. The subfamily Homalometroninae contains marine, brackish-, and fresh-water species. Manter (1963) discussed the geographical dispersal of the group and the possible significance of present distribution for the phylogeny and evolution of the parasites and of their hosts. In his opinion, the subfamily illustrates an evolution from marine ancestors, through secondary-division hosts, to become parasites of fresh-water fishes. Results of the present investiga...

The genus Asymphylodora was erected by Looss (1899) to contain Distoma perlatum von Nordmann, 1832, a parasite from the intestine of Cyprinus tinca, as type species. Rudolphi (1809) had suggested and Looss agreed that the species is identical with Fasciola tincae Modeer, 1790, from the same host. In the genus Asymphylodora, Looss included Distoma exspinosum Hausmann, 1896 from the intestine of Barbus fluviatilus and Distoma imitans Miihling, 1898 from the intestine of Abramis brama. Distoma ferruginosum von Linstow, 1877 from the intestine of Barbus fluviatilus, was considered identical with D. perlatum. Fasciola globiporum Rudolphi, 1802 was listed as Distoma globiporum by Rudolphi (1809) who stated that it included F. tincae and several other inadequately described trematodes. Looss (1894) had given a detailed description of D. perlatum and although he admitted the identity of this species and F. tincae, he did not make the correct taxonomic revision when he erected the genus Asymphylodora. Liihe (1909) made the combination Asymphylodora tincae (Modeer, 1790); he recognized the validity of Distoma ferruginosum, which he included with the three species selected by Looss as members of the genus. Distoma punctatum Zeder, 1800 from the intestine of Cyprinus barbus, was listed as probably identical with Asymphylodora ferruginosum. All of these worms were from the intestine of cyprinid fishes of Europe. Subsequently, members of the genus have been reported from various parts of the world. Isaichikov (1923) described specimens from cyprinid fishes of the Kuban River as Asymphylodora tincae kubanicum, and this form was re-described by Markewitsch (1951). Ozaki (1925) described Asymphylodora macrostoma from several species of fishes in Japan. Ivanitskii (1928) described Asymphylodora dneproviana from fishes in the Ukraine. Witenberg and Eckmann (1934) found worms in Cyprinus carpio in Syria which they identified as A. tincae. After noting the variability manifested by different individuals, they declared that all previously described species were identical and accordingly, all other specific names were reduced to synonymy with A. tincae. Markowski (1935) described Asymphylodora demeli from Gobius minutus, taken in the coastal waters of Poland. He

Taeniocotyle nom. nov. is proposed to replace Macraspis Olsson, 1869, homonym of Macraspis MacLeay, 1819, a coleopterous insect. It designates certain trematode worms, from the gall-bladders of selachian fishes, that belong to the family Aspidogastridae Poche, 1907 and the order Aspidobothrea Burmeister, 1856. The systematic position of this group, often regarded as intermediate between the Monogenea and Digenea, is reviewed. From morphological and developmental evidence, the Aspidobothrea and Digenea are included in the subclass Malacobothridia Burmeister, 1856.

In one of his last publications, Joseph Leidy (1891) described a larval trematode, Distomum lasium, from the digestive gland and gonad of Ilyanassa obsoleta at Beach Haven, New Jersey. The account, although brief, was sufficiently complete and definitive to permit positive identification of the species. Leidy reported that I. obsoleta was very abundant on the mud flats near Beach Haven and that on dissecting a number he “? foundthat one in five or six was infested with the larval distomas enclosed in sponocysts, often in large numbers, embedded intheliverand associated genitalgland. The larvaealways appeared in the distoma-form and never as a cercaria.― He noted the shape and size of the sporocysts and of the tailless larvae, and for the latter he recorded the size of suckers, form of the excretory bladder, presence of spines on cuticula, and stylet in the dorsal wall of the oral sucker. This Species was reported by Linton (1915) from the same host at Woods Hole, Massachusetts. During the summers of 1909 and 1910 he had examined over one thousand specimens of I. obsolela and a record of his dissections is presented. Apparently unaware of Leidy's earlier paper, Linton gave a description of the sporocyst and the cercariaeum, but did not name the species. A comparison of the descriptions of Leidy and Linton shows substantial agreement and leaves no doubt concerning the identity of the parasites collected in New Jersey and Massachusetts. The account of Linton was confirmed and augmented by Miller and Northup (1926). These authors had likewise overlooked the reportofLeidy and they named the larvaCercariaeumlintoni.In a study of the seasonal infestation of Nassa obsolela with larval trema todes,theyexamined 8,875individuals collected from a limitedareain QuamquissetHarbornearWoods Hole, and found Cercariaeumlintoni

Metacercarial stages of a strigeid trematode were reported from the brain and eyes of Menidia menidia and Mugil cephalus at Beaufort, North Carolina by Hunter and Vernberg (1960) and from the brain of Fundulus heteroclitus taken in Chesapeake Bay by Abbott (1968). Strigeid metacercariae occur also on the brain of species of Fundulus in the Woods Hole, Massachusetts region. The only strigeid cercaria described from mid-Atlantic coast is Cercaria nassa Martin 1945. Attempts to infect Fundulus spp. with C. nassa were futile and attempts to infect avian species, egrets, herons, cormorants, and gulls with metacercariae from Fundulus heteroclitus gave only negative results. The cercaria and metacercaria are described. Cercaria nassa belongs to the larval group, Diplostomulum, and is named Diplostomum nassa (Martin, 1945), family Diplostomidae. The metacercaria from the brain of F. heteroclitus belongs to the larval group, Tetracotyle, family Strigeidae. Accordingly, the two larvae are members of entirely differ...

When eggs ofMonieza expansaare fed to galumnid mites, the onchospheres emerge in the intestine and migrate to the body cavity. Here they undergo metamorphosis and develop into cysticercoids. The dissection of mites, at various intervals after exposure, has yielded a successive series of developmental stages. Protocols of the experiments and photographs of living larvae are presented. These results demonstrate that mites serve as intermediate hosts ofMoniezia, and probably also of other anoplocephaline cestodes.

Summary The problem of specific identity in the genus Bertiella is discussed. Three mature cestodes from a monkey, Macacus rhesus, are identified tentatively as Bertiella studeri. The animal probably acquired the infection in India, but had been in Hamburg for at least six months. The worms and eggs are described and life history experiments are reported. Eggs from gravid proglottids were fed to twenty-four species of free-living mites, collected from different locations in the vicinity of Hamburg. Onchospheres and developing larvae were recovered from the body cavity of Notaspis coleoptratus, Scutovertex minutus, Scheloribates laevigatus and Galumna sp. Cysticercoids were removed from S. laevigatus and Galumna sp. They were spherical, to oval, to pyriform, 0.1 to 0.15 mm. in diameter, and provided with small cercomeres. It is clear therefore that Bertiella, like other anoplocephaline cestodes, Moniezia and Cittotaenia, utilizes free-living mites as intermediate hosts.

Linton (1940) described the adult stage of Zoogonoides laevis and distinguished between this species and Z. viviparus (Olsson, 1868) Odhner, 1902, the type and only other known representative of the genus. He found the worms in the intestine of Tautoga onitis and an immature specimen from the round herring, “? Etrumensadina― (= Etrumeus teres) was referred provisionally to Z. laevis. During the summer of 1942, tailless cercariae were found emerging from Columbella (= Mitrella Rizzo) lunata collected in the Woods Hole region. -Their striking resemblance to the cercariae of Zoogonus lasius (Leidy, 1891) Stunkard, 1940 indicated that the two were closely related. Furthermore, their morpho logical agreement with Zoogonoides laevis suggested that they might be larvae of the latter species. Experiments demonstrated the correctness of the hypothesis and the successive stages in the life cycle have been obtained. The cercariae develop in sporocysts in the lymph spaces of C. lunata, penetrate into Nereis virens where they become metacercariae, and sexual maturity is attained in the intestine of T. onitis. The eggs are large, without shells, and contain active, ciliated miracidia when extruded. The larvae hatch in sea water and invade the snails where the asexual generations are produced. The life history was reported in abstract (Stunkard, 1942).

During the spring and summer of 1948 at the Scripps Institution of Oceanography, La Jolla, California, one of us (H. W. S.) examined various marine invertebrates for possible stages in the life-history of the mesozoan parasites of octopuses.2 In dissections of the common sand-dollar, Dendraster eccentricus, several specimens of a rhabdocoel turbellarian were found. Whether they were originally in the intestine or the perivisceral cavity was not determined. Two specimens were fixed in Duboscq-Brasil solution, stained with Paracarmine, and mounted. Attempts at identification showed them to be different from all previously described species. Accordingly, preliminary sketches were made and the larger one was demounted, cut transversely in serial sections at 10 microns, and stained with haematoxylin and erythrosin. The presence of a large egg-capsule in each worm obscured certain structures in the whole mounts, and in the sectioned specimen, the adjacent structures were obviously distorted by pressure. So far as we have been able to determine, this is the first rhabdocoel parasite to be described from the flattened, sand-dollar type of echinoid and the fifth species of the family Umagillidae reported from the Western Hemisphere. The morphology of the worms and review of the literature indicated their inclusion in the genus Syndesmis. Since the specimens could not be referred to any known species, they are described as a new species for which the name Syndesmis dendrastrorum is proposed.

The various stages in the life history of Cryptocotyle lingua are identified and described. Adults naturally occur in the intestine of fish-eating birds and mammals. They were experimentally obtained in the cat, white rat, and guinea-pig. The development of the miracidium was followed within the egg. Larval stages occur in the marine snail, Littorina littorea. The structure of the redia and cercaria is described in detail, and evidence is submitted to show that the cercaria is identical with Cercaria lophocerca Lebour, described from the same snail on the British coast. Penetration and encystment of the cercaria in the skin of the cunner were experimentally secured. Excystment of the metacercaria was obtained both in experimental animals and in vitro. The metacercariae were maintained in culture media for as long a time as is required for them to attain sexual maturity in the final host. The host relations and specificity of the parasite are discussed on the basis of infection experiments. The cercaria is compared with similar larvae and its taxonomic position determined.

The advantages and difficulties of various methods employed in the study of larval trematodes are discussed. The desirability of using living specimens rather than fixed material and of studying mature, normally emerged cercariae rather than those obtained by crushing the host is noted. Intra-vitam staining with neutral red is recommended to demonstrate the form and reaction of the secretory granules in gland cells. Knowledge of the details of the excretory system is of major importance in both theoretical and experimental work.

Seven species of cercariae and four of metacercariae collected at Roscoff, Finistère, during August, 1931, are described. They have been referred to appropriate systematic groups and wherever possible, probabilities concerning life histories are suggested. Four of the cercariae and two of the metacercariae are recorded as new to science.

1. The life-history of Microphallus similis has been worked out by experimental infection of both intermediate and final hosts.2. Encysted metacercariae from Carcinides maenas developed to sexual maturity in Larus argentatus and Sterna hirundo. Eggs of the parasite developed in these hosts were used to infect Littorina obtusata. Two generations of sporocysts were recovered.3. Littorina saxatilis and Littorina littorea also harbor the asexual generations at Woods Hole, Massachusetts.4. The cercariae are minute, stylet-bearing monostomes and small green crabs, C. maenas, exposed to these cercariae became heavily infected; enormous numbers of larvae entered the tissues and developed into metacercariae identical with those of natural infections. Small crabs, each exposed continuously to the cercariae from six to eight infected snails, died in ten to twenty days and on dissection each yielded thousands of larvae.5. The stages in the life-cycle of the parasite agree with descriptions by European investigators o...

The genus Renicola was erected by Cohn (1904) to contain Monostomum pingue (Mehlis in Creplin, 1846), when he discovered that the species has a distinct acetabulum and could no longer be regarded as a monostome. He studied the original material of Mehlis, from the kidneys of the crested grebe, Podiceps cristatus, in both whole-mount preparations and serial sections. He noted that the worms, although hermaphroditic, live in pairs in expansions of the renal tubules, that there is no copulatory organ, and that the acetabulum is so obscured by eggs in the uterus that it is quite invisible in whole-mount preparations. In this paper he advanced the idea that adhesive organs of trematodes which live in closed cavities do not function actively and accordingly either fail to develop or undergo atrophy and become reduced in size. The second and third species of the genus, Renicola secunda and R. tertia, were described by Skrjabin (1924) from the white pelican, Pelecanus onocrotalus, and from the tern, Sterna fluviatilis, respectively, both taken in Russian Turkestan. The descriptions are brief, listing sizes of body and of eggs, but the figures give other pertinent information. The three species of Renicola were characterized by shape of body, including the degree of posterior extension, the relative length of the digestive ceca, and the location and extent of the vitellaria. However, Skrjabin stated that because of meager material, specific determination was uncertain. Yamaguti (1958) listed Renicola zarudni Skrjabin, 1927, from a pelican taken by the 28th Helminthological Expedition of the U.S.S.R. to Turkestan. However, there is no reference to R. zarudni in Skrjabin, Trematodes of Animals and Man, vol. 1, pp. 261-277 (1947), which deals with the genus Renicola. Odening (1962b) listed R. zarudni as a nomen nudum and the species as identical with R. secunda Skrjabin, 1924. The next species of the genus was described by Witenberg (1929) from Puffinus kuhli, taken by the Sinai Expedition of the Hebraischen Universitaet, Jerusalem, to the Suez. Witenberg noted that the descriptions of the previously named species were so incomplete that determination of new material should be made with caution. To identify the specimens from P. kuhli, they were designated provisionally as a new species, Renicola glandoloba, although Witenberg admitted the possible identity of the previously described species with the new species described by him.

The genus Renicola Cohn, 1904, was based on Monostoma pingue (Mehlis in Creplin, 1846) ; it is cosmopolitan in distribution and species have been found in the kidneys of birds belonging to various families. Cercaria rhodometopa , Perez, 1924, has a similar excretory system and the rhodometopous cercariae have been regarded as renicolid larvae, although attempts at experimental infections have so far proved futile. Cable (1963) reported that certain plagiorchid cercariae are larvae of renicolid species and postulated that species of Renicola may have two types of cercariae, either rhodometopous or plagiorchid larvae. Stunkard (1964) described plagiorchid cercariae from Thais lapiltus and their development in the renal tubules of gulls, Larus argentatus , to adults that were identified as a new species, Renicola thaidus . He noted that these cercariae are similar to others from Littorina spp., viz., Cercaria parvicaudata , Stunkard and Shaw, 1931, and Cercaria roscovita , Stunkard, 1932. Werding (1969) reported that metacercariae of C. roscovita developed in the kidneys of L. argentatus to adults identified as Renicola roscovita (Stunkard, 1932). He suggested the identity of C. roscovita and C. parvicaudata . Robson and Williams (1970) identified cercariae from Littorina littorea as Cercaria A ; the larvae agreed morphologically with C. roscovita , but attempts to infect juvenile L. argentatus , ducklings, chicks and various laboratory mammals failed. Repeated attempts by the writer to infect L. argentatus and other birds with metacercariae of C. parvicauda have given only negative results. The systematic position of the rhodometopodous cercariae is enigmatic, but the inclusion of such morphologically diverse types as the plagiorchid and rhodometopodous cercariae in a single genus controverts ideas of generic unity.

The metacercarial stage of Ascocotyle (Phagicola) diminuta Stunkard and Haviland, 1924 has been found encysted in the gills of Fundulus heteroclitus. Experimental infections of rats, mice, hamsters, Larus argentatus and Nycticorax nycticorax have yielded adult worms and permitted additions and emendations to the description of the parasite.

Metacercariae from Limulus polyphemus developed to sexual maturity in white mice and golden hamsters. The worms are described as a new species, Microphallus limuli. Morphologically they are very similar to M. claviformis (Brandes, 1888), but bionomic features seem to preclude their allocation to that species. The genus Microphallus is discussed, Spelophallus Jagerskiold, 1908 is suppressed as a synonym and S. primus Jagerskiold, 1908, the only known species, is transferred to Microphallus as M. primus (Jagerskiold, 1908). In agreement with Cable and Kuns (1951), the family Maritrematidae Baer, 1943 is not accepted.

Cercaria quissetensis Miller and Northup, 1926 has been restudied. It is the only echinostome cercaria which has been found in the examination of over 18,000 specimens of Nassa obsolela at Woods Hole. This cercaria encysts in the gills, mantle and foot of various mollusks. Metacercariae were obtained experimentally in Mya arenaria, Modiolus modiolus, Mytilus edulis, Cumingia tellinoides, Pecten irradians, Ensis directus, and Crepidula fornicata. The metacercariae are infective for birds three days after encystment and develop to maturity in the herring gull, Larus argentatus. Sexually mature specimens are identical with certain of those described by Linton (1928) as Himasthla elongata (Mehlis). Since there are important differences between the present specimens and H. elongata, they cannot be referred to that species and the name of the cercaria is adopted for them. Possible synonymy in the genus Himasthla is discussed.

A critical review of the Sporozoa is presented with consideration of changes in taxonomic arrangement as different morphological and developmental features have influenced opinion on systematics in the group. Infections of fishes receive primary attention, especially those produced by members of the Microsporidia. Although chiefly parasites of invertebrates, certain species cause severe infections in fishes. The bionomics, life cycles, and taxonomy of these species are still equivocal.

The digenetic trematode described by Linton (1900) as Distoma pyriforme has been reported from many hosts and several species have been included in the accounts, with resultant confusion. It was included in the genus Lepocreadium Stossich, 1904 by Linton (1940), but it is not congeneric with L. album (Stossich, 1890), type of the genus. Its life-cycle has been elucidated; Anachis avara is the first intermediate host, where cercariae are produced in rediae. The cercariae are ophthalmotrichocercous, swim actively with the tail in advance. They penetrate but do not encyst in certain hydrozoan and scyphozoan medusae and in the ctenophore, Mnemiopsis leidyi. Developmental and adult stages resulted from ingestion of metaceracariae by the scup, Stenotomus chrysops. Eggs from worms were embryonated; miracidia emerged in 8 to 10 days, penetrated into A. avara, transformed into sporocysts, and produced rediae in 5-6 weeks. Worms recovered from S. chrysops are assigned to a new genus, Neopechona, and redescribed as ...

Consideration of the organization, ontogeny, and orientation of tapeworms, and comparison with the structure and development of other invertebrates, support the opinion that the cestode is an individual rather than a colony and that the transformation of the oncosphere to a procercoid or cysticercoid is a true metamorphosis in which there is a reversal of the antero-posterior axis. T EAPEWORMS have been known for thousands of years, and the ancients believed that both the segmented and bladder-worm stages arose spontaneously in the bodies of other animals. In the middle of the last century, Kiichen

The validity of species in the genus Himasthla is discussed; Echinostoma annulatum (Diesing, 1850) is transferred to Himasthla and H. tensa Linton, 1940 is suppressed as a synonym of H. elongata (Mehlis, 1831). A specimen from Nycticorax nycticorax, tentatively assigned to H. elongata, is very similar to H. secunda (Nicoll, 1906), which suggests the possibility that H. secunda may be a not-fully mature form of H. elongata. Three new species are described; H. mcintoshi from Numenius americanus americanus taken in Tooele County, Utah; H. piscicola, probably an accidental infection, from the South American fish, Arapaima gigas; and H. compacta from experimental infection of the herring gull, Larus argentatus. The life cycle of H. compacta has been traced; the asexual generations occur in Hydrobia minuta, the cercariae encyst in Mya arenaria and probably other mollusks.

A chronological account of the genus Azygia discloses discordant observations and divergent opinions. Dawes (1946) recognized only a single species, A. lucii, in Europe. In it he included A. robusta Odhner, 1911, which reaches a length of 47 mm. and Ptychogonimus volgensis von Linstow, 1907, which measures 5 to 6 mm. in length and had been transferred to Azygia as a valid species by Odhner (1911). In America several species have been described, but there is no agreement on the number that are distinct and valid. In fact, there is no adequate information on the extent of variation that occurs in a natural species, and consequently on the features that can be relied on to distinguished between species. This situation is not peculiar to Azygia, but obtains in many genera. It is the natural result of development by members of a parasitic species in different hosts, invertebrate and vertebrate, often of different taxonomic groups, which differ in their nutritional and other physiological conditions, and accord...

The life history of Parorchis avitus has been experimentally traced. The cercariae occur in the marine snails, Urosapinx cinereusand Thais (Purpura) lapilius. Adults have been obtained from the cloaca of the common tern, Sterna hirundo, and the roseate tern, Sterna dougalli, after feeding the young birds with encysted larvae.It has been shown that a specific secondary intermediate host is not essential for the completion of the life history; only a means of transference is necessary.Additional morphological differences between Parorchis avitus and Parorchis acanthus are described.

A description of Zalophotrema hepaticum is presented. Study of this species and review of the literature show that the genera assigned to the two families, Fasciolopsidae and Campulidae, may be included in a single family. Furthermore, since Fasciola is the nomenclatorial type of the family to which it belongs, the rules of nomenclature do not permit the substitution of the name Fasciolopsidae for Fasciolidae. Consequently the family Fasciolidae is restored with three sub-families, Fasciolinae, Fasciolopsinae, and Campulinae. A new genus, Synthesium, is erected to contain Distomum tursionis Marchi.