Amphistomes Classification Essay

Anderson, M. G. & Anderson, F. M. (1963). Life history of Proterometra dickermani Anderson, 1962. Journal of Parasitology49, 275–80.

Bayliss, H. A. (1938). Helminths and evolution. In Evolution Essays on Aspects of Evolutionary Biology presented to Professor E. S. Goodrich on his Seventieth Birthday (ed. De Beer, G. R.), pp. 249–70. Oxford: Clarendon Press.

Bayssade-Dufour, C. (1979). L'appareil sensoriel des cercaires et la systematique des trématodes digénétiques. Mémoires du Muséum National d'Histoire Naturelle, Ser. A, Zoologie113, 1–81.

Bowers, E. A. & James, B. L. (1967). Studies on the morphology, ecology and life-cycle of Meiogymnophallus minutus (Cobbold, 1859) comb. nov. (Trematoda: Gymnophallidae). Parasitology57, 281–300.

Bozhkov, D. K. (1982). [Helminth Life-cycles and their Evolution.](In Bulgarian.) Sofia: Durzhavno Izdatelstvo Nauka i Izkustvo.

Bray, R. A. (1986). Patterns in the evolution of marine helminths. In Parasitology–quo vadit?, Proceedings of the Sixth International Congress of Parasitology, Brisbane (ed. Howell, M. J.), pp. 337–44. Canberra: Australian Academy of Sciences.

Bray, R. A. (1987). A discussion of the status of the subfamily Baccigerinae Yamaguti, 1958 (Digenea) and the constitution of the family Fellodistomidae Nicoll, 1909. Systematic Parasitology (in the Press).

Bray, R. A. & Gibson, D. I. (1977). The Accacoeliidae (Digenea) of fishes of the north-east Atlantic. Bulletin of the British Museum (Natural History) (Zoology) 31, 51–99.

Bray, R. A. & Gibson, D. I. (1980). The Fellodistomidae (Digenea) of fishes from the north-east Atlantic. Bulletin of the British Museum (Natural History) (Zoology) 37, 199–293.

Brooks, D. R. (1982). Higher level classification of parasitic platyhelminths and fundamentals of cestode classification. In Parasites-their World and Ours, Proceedings of the Fifth International Congress of Parasitology, Toronto, 1982 (ed. Mettrick, D. F. and Desser, S. S.), pp. 189–93. Amsterdam: Elsevier Biomedical.

Brooks, D. R., O'Grady, R. T. & Glen, D. R. (1985a). The phylogeny of the Cercomeria Brooks, 1982 (Platyhelminthes). Proceedings of the Helminthological Society of Washington52, 1–20.

Brooks, D. R., O'Grady, R. T. & Glen, D. R. (1985b). Phylogenetic analysis of the Digenea (Platyhelminthes: Cercomeria) with comments on their adaptive radiation. Canadian Journal of Zoology63, 411–43.

Cable, R. M. (1965). ‘Thereby hangs a tail’. Journal of Parasitology51, 2–12.

Cable, R. M. (1974). Phylogeny and taxonomy of trematodes with reference to marine species. In Symbiosis in the Sea (ed. Vernberg, W. B.), The Belle W. Baruch Library in Marine Science, no. 2, 173–93. Columbia, South Carolina: University of South Carolina Press.

Cable, R. M. (1977). An Illustrated Laboratory Manual of Parasitology. Minneapolis: Burgess.

Cable, R. M. & Crandall, R. B. (1956). Larval stages and phylogeny as exemplified by the lung fluke of turtles. Science124, 890.

Cannon, L. R. G. (1986). The Pterastericolidae: parasitic turbellarians from starfish. In Parasitic Lives. Papers on Parasites, their Hosts and their Associations, to Honour J. F. A. Sprent (ed. Cremin, M.et al.), pp. 15–32. St Lucia, London and New York: University of Queensland Press.

Ching, H. L. (1982). Description of germinal sacs of a gymnophallid trematode Cercaria margaritensis sp. n., in the extrapallial fluid of subtidal snails (Margarites spp.) in British Columbia. Canadian Journal of Zoology60, 516–20.

Ciordia, H. (1956). Cytological studies of the germ cell cycle of the trematode family Bucephalidae. Transactions of the American Microscopical Society75, 103–16.

Clark, R. B. (1964). Dynamics in Metazoan Evolution. The Origins of the Coelom and Segments. Oxford: Clarendon Press.

Colbert, E. H. (1955). Evolution of the Vertebrates. New York: John Wiley.

Crandall, R. B. (1960). The life history and affinities of the turtle lung fluke, Heronimus chelydrae MacCallum, 1902. Journal of Parasitology46, 289–307.

Cribb, T. H. (1987). Pseudophyllodistomum gen. nov. (Digenea, Gorgoderidae) from Australian and Asian freshwater fishes. Journal of Natural History (in the Press.)

Cribb, T. H. & Pearson, J. C. (1986). Production of miracidia by cyathocotylid sporocysts and its implications for the evolution of the Digenea. ICOPA VI. Handbook Supplement. Abstract no. 759, p. 8.

Dawes, B. (1936). Sur un tendance probable dans l'evolution des trématodes digénétiques. Annales de Parasitologie humaine et comparée14, 177–82.

Dujardin, F. (1845). Histoire Naturelle des Helminthes ou vers Intestinaux. Paris: Libraire Encyclopédie de Roret.

Ehlers, U. (1984). Phylogenetisches System der Plathelminthes. Verhandlungen des naturwissen-schaftlichen Vereins, Hamburg (NF) 27, 291–4.

Ehlers, U. (1985a). Phylogenetic relationships within the Platyhelminthes. In The Origins and Relationships of the Lower Vertebrates, (ed. Conway, S. Morris), pp. 143–58. Oxford: Clarendon Press.

Ehlers, U. (1985b) Das Phylogenetische System der Plathelminthes. Stuttgart: Gustav Fischer Verlag.

Fuhrmann, O. (1928). Zweite Klasse des Cladus Plathelminthes. Trematoda. In Handbuch der Zoologie, (ed. Kukenthal, W. and Krumbach, T.). Berlin and Leipzig: Walter de Gruyter.

Gibson, D. I. (1981). Evolution of digeneans. In Workshop on Evolution of Helminths. IV. European Multicolloquium of Parasitology. Parasitology82, 161–3.

Gibson, D. I. (1983). The systematics of ascaridoid nematodes - a current assessment. In Concepts in Nematode Systematics, Systematics Association Special, Vol. 22, (ed. Stone, A. R.et al.), pp. 321–88. London and New York: Academic Press.

Gibson, D. I. & Bray, R. A. (1977). The Azygiidae, Hirudinellidae, Ptychogonimidae, Sclerodistomidae and Syncoeliidae (Digenea) of fishes from the north-east Atlantic. Bulletin of the British Museum (Natural History), (Zoology) 32, 167–245.

Gibson, D. I. & Bkay, R. A. (1979). The Hemiuroidea: terminology, systematics and evolution. Bulletin of the British Museum (Natural History) (Zoology) 36, 35–146.

Gibson, D. I. & Chinabut, S. (1984). Rohdella siamensis gen. nov., sp. nov. (Aspidogastridae: Rohdellinae subfam. nov.) from freshwater fishes in Thailand, with a reorganization of the Aspidogastrea. Parasitology88, 383–93.

Gibson, D. I. & Valtonen, E. T. (1984) How do the helminth parasites of fishes survive in the frozen north?Parasitology89, xlix.

Gould, S. J. (1977). Ontogeny and Phytogeny. Cambridge, Mass: Harvard University Press.

Gu, C. & Shen, J. (1983). Digenetic trematodes of fishes from the Xisha Islands, Guandong Province, China, Studia Marina Sinica20, 157–84 (In Chinese, with English summary.)

Guilford, H. G. (1958). Observations on the development of the miracidium and germ cell cycle in Heronimus chelydrae MacCallum (Trematoda). Journal of Parasitology44, 64–74.

Hendelberg, J. (1986). The phylogenetic significance of sperm morphology in the Platyhelminthes. Hydrobiologia132, 53–8.

Howell, M. (1966). A contribution to the life history of Bucephalus longicornutus (Manter, 1954). Zoology Publications of Victoria University of Wellington40, 1–42.

James, B. L. (1964). The life-cycle of Parvatrema homoeotecnum sp. nov. (Trematoda: Digenea) and a review of the family Gymnophallidae Morozov, 1955. Parasitology54, 1–41.

James, B. L. (1980). Studies on marine Digenea. D.Sc. thesis, University College, Swansea.

James, B. L. & Bowers, E. A. (1967). Reproduction in the daughter sporocysts of Cercaria bucephalopsis hairneana (Lacaze-Duthiers, 1854) (Bucephalidae) and Cercaria dichotoma Lebour, 1911 (non Müller) (Gymnophallidae). Parasitology57, 607–25.

Køie, M. (1985a). On the morphology and life-history of Lepidapedon elongatum (Lebour, 1908) Nicoll, 1910 (Trematoda, Lepocreadiidae). Ophelia24, 135–53.

Køie, M. (1985b). The Surface Topography and Life-cycles of Digenetic Trematodes in Limanda limanda (L.) and Gadus morhua L. Summary of Doctoral thesis, University of Copenhagen.

Kniskern, V. B. (1952). Studies on the trematode family Bucephalidae Poche, 1907. II. Transactions of the American Microscopical Society71, 317–40.

La Rue, G. R. (1957). The classification of digenetic Trematoda: a review and a new system. Experimental Parasitology6, 306–19.

Lebour, M. V. (1912). A review of the British marine cercariae. Parasitology4, 416–56.

Leuckart, R. (1879). Die Parasiten des Menschen und die von ihnen Herrührenden Krankheiten. Leipzig und Heidelberg: C. F. Winter'sche.

Le Zotte, L. A.Jr (1954). Studies on marine digenetic trematodes of Puerto Rico: the family Bivesiculidae, its biology and affinities. Journal of Parasitology40, 148–62.

Lynch, J. E. (1933). The miracidium of Heronimus chelydrae MacCallum. Quarterly Journal of the Microscopical Society76, 13–33.

MacCallum, G. A. (1921). Studies in helminthology. 1. Zoopathologica1, 191–3.

MacCallum, W. G. (1902). Heronimus chelydrae nov. gen., nov. sp. A new monostome parasite of the American snapping turtle. Zentralblatt für Bakteriologie, Parasitenkunde, Infektionskrankheiten (und Hygiene)33, 632–6.

Malmberg, G. (1986). The major parasitic platyhelminth classes–progressive and regressive evolution?Hydrobiologia132, 23–9.

Matthews, R. A. (1973). The life-cycle of Prosorhynchus crucibulum (Rudolphi, 1891) Odhner, 1905, and a comparison of its cercaria with that of Prosorynchus squamatus Odhner, 1905. Parasitology66, 133–64.

Nielsen, C. & Nørrevang, A. (1985). The trochaea theory: an example of life cycle phylogeny. In The Origins and Relationships of the Lower Invertebrates. The Systematic Association Special, vol. 28 (ed. Conway, S. Morris et al.), pp. 28–41. Oxford: Clarendon Press.

Odening, K. (1961). Historische und moderne Gesichtspunkte beim Aufbau eines natürlichen Systems der digenetischen Trematoden. Biologische Beiträge1, 73–90.

Odening, K. (1974). Verwandtschaft, System und zyklo-ontogenetische Besonderheiten der Trematoden. Zoologischer Jahrbucher, Systematik. 101, 345–96. (Translation: Agence Tunisienne de Public-Relations, Tunis, 1977).

Odening, K. (1975). Nature and development of the parthenitae in the trematode genus Azygia. Proceedings of the Second European Multicolloquium of Parasitology, Trogir, pp. 111–18.

Odening, K. (1976). Der Lebenszyklus von Azygia lucii (Trematoda) - Untersuchungen im Gebiet der DDR. Biologisches Zentralblatt95, 57–94.

Odhner, T. (1905). Die Trematoden des arktischen Gebietes. Fauna Arctica4, 289–372.

O'Grady, R. T. (1985). Ontogenetic sequences and the phylogenetics of parasitic flatworm life cycles. Cladistics1, 159–70.

Ozaki, Y. (1937). Studies on the trematode families Gyliauchenidae and Opistholebetidae, with special reference to lymph system. II. Journal of Science of the Hiroshima University, Series B, Division 1 (Zoology) 5, 167–244.

Padilha, T. N. (1978). Caracterizacao de familia Zonocotyle bicaecata Travassos, 1948 e descricao de un novo gênero (Trematoda, Digenea). Revista Brasileira de Biologia38, 415–29.

Palombi, A. (1942). I ciclo biologico di Ptychogonimus megastoma (Rud.). Osservazioni sula morfologia e fisiologia delle forme larvali e considerazioni filogenetiche. Rivista di Parassitologia6, 117–72.

Pearson, J. C. (1968). Observations on the morphology and life-cycle of Paucivitellosus fragilis Coil, Reid & Kuntz, 1965 (Trematoda Bivesiculidae). Parasitology58, 760–88.

Pearson, J. C. (1972). A phylogeny of life-cycle patterns of the Digenea. Advances in Parasitology10, 153–89.

Poche, F. (1926). Das System der Platodaria. Archiv für Naturgeschichte1925, 1–458.

Popiel, I. & James, B. L. (1978a). Variations in the ultrastructure of the daughter sporocyst of Microphallus pygmaeus (Levinson, 1881) (Digenea: Microphallidae) in chemically defined media. Parasitology76, 349–58.

Popiel, I. & James, B. L. (1978b). The ultrastructure of the tegument of the daughter sporocyst of Microphallus similis (Jäg., 1900) (Digenea: Microphallidae). Parasitology76, 359–67.

Premvati (1955). Cercaria multiplicata n. sp. from the snail Melanoides luberculatus (Müller). Journal of the Zoological Society of India7, 13–24.

Rohde, K. (1971). Phylogenetic origin of trematodes. Parasitologische Schriftenreihe21, 17–27.

Rohde, K. (1972). The Aspidogastrea, especially Multicotyle purvisi, Dawes, 1941. Advances in Parasitology10, 77–151.

Rohde, K. & Watson, N. (1987). Ultrastructure of the protonephridial system of larval Austramphilina elongata (Platyhelminthes, Amphilinidea). Journal of Submicroscopical Cytology19, (in the Press).

Rudolphi, C. A. (1801). Beobachtungen über die Eingeweidewürmer. Archiv für Zoologie und Zootomie2, 1–65.

Sakaguchi, S. (1968). Studies on the life-history of the trematode parasitic in pearl oyster Pinctada fucata, and on the hindrance for pearl culture. Bulletin of the National Pearl Research Laboratory13, 1635–88 (In Japanese, English summary.)

Sewell, R. B. S. (1922). Cercariae indicae. The Indian Journal of Medical Research10, Suppl. 1–370 + iii.

Shen, J. W. (1985). Digenetic trematodes of fishes from the Xisha Islands, III. (Larval forms). Sludia Marina Sinica24, 181–8.

Sinitzin, D. F. (1911). [Parthenogenetic generation of trematodes and their progeny in molluscs of the Black Sea.] Zapiski Imperatorskoi Akademii Nauk po Fiziko-Matematicheskomu Otdeleniyu30 (5), 1–127 (In Russian, English translation in BM(NH) arranged by G. R. La Rue, University of Michigan, 1925.)

Sinitzin, D. F. (1931). Studien über die Phylogenie der Trematoden. IV. The life histories of Plagioporous siliculus and Plagioporus virens, with special reference to the origin of the Digenea. Zeitschrift für wissenschaftliche Zoologie138, 409–56.

Skrjabin, K. I. (1947). [Family Bivesiculidae Yamaguti, 1938]. Osnovy Trematodologii1, 46–53. (In Russian.)

Skrjabin, K. I. & Gushanskaja, L. Kh. (1962). [Order Bucephalidida (Odening, 1960) Skrjabin & Guschanskaja, 1962.] Osnovy Trematodologii20, 165–559. (In Russian.)

Sluys, R. (1984). The meaning and implications of genealogical tree diagrams. Zeitschrift für zoologische Systematik und Evolutionsforschung22, 1–8.

Smith, J.III & Tyler, S. (1985). The acoel turbellarians: kingpins of metazoan evolution or a specialized offshoot. In The Origin and Relationships of Lower Invertebrates. The Systematic Association Special, vol. 28, (ed. S., Conway Morriset al.), pp. 123–42. Oxford: Clarendon Press.

Sprent, J. F. A. (1983). Observations on the systematics of ascaridoid nematodes. In Concepts in Nematode Systematics, Systematics Association Special, vol. 22, (ed. Stone, A. R.et al.), pp. 303–19. London and New York: Academic Press.

Stunkard, H. W. (1946). Inter-relationships and taxonomy of the digenetic trematodes. Biological Reviews21, 148–58.

Stunkard, H. W. (1956). The morphology and life-history of the digenetic trematode, Azygia sebago Ward, 1910. Biological Bulletin, Marine Biological Laboratory, Woods Hole, Mass. 111, 248–68.

Tennent, D. H. (1906). A study of the life history of Bucephalus haimeanus; a parasite of the oyster. Quarterly Journal of Microscopical Science49, 635–90.

Tennent, D. H. (1909). Account of experiments for determining the complex life cycle of Gasterostomum gradlescens. Science29, 432–3.

Thulin, J. (1981). On the morphology and early development of the marine fish blood-fluke Aporocotyle simplex Odhner, 1900 (Digenea: Sanguinicolidae). Ph.D. thesis, University of Göteborg.

Ulmer, M. J. & Sommer, S. C. (1957). Development of sporocysts in the turtle lung fluke, Heronimus chelydrae MacCallum (Trematoda: Heronimidae). Proceedings of the Iowa Academy of Science64, 601–13.

Valtonen, E. T., Gibson, D. T. & Kurttila, M. (1984). Trematodes in northern Finland. I. Species maturing in fish in the northeastern Bothnian Bay and in a local lake. Bothnian Bay Reports3, 31–43.

Waterman, T. H. (1961) Light sensitivity and vision. In The Physiology of the Crustacea, vol. 2. Sense Organs, Integration, and Behaviour (ed. Waterman, T. H.), pp. 1–64. London and New York: Academic Press.

Woodhead, A. E. (1931). The germ-cell cycle in the trematode family Bucephalidae. Transactions of the American Microscopical Society50, 169–87.

Wright, C. A. & Southgate, V. S. (1981). Coevolution of digeneans and molluscs, with special reference to schistosomes and their intermediate hosts. In The Evolving Biosphere, (ed. Forey, P. L.), pp. 191–205. British Museum (Natural History). Cambridge: Cambridge University Press.

Yamaguti, S. (1934). Studies on the helminth fauna of Japan. 2. Trematodes of fishes I. Japanese Journal of Zoology5, 249–541.

Yamaguti, S. (1970). The Digenetic Trematodes of Hawaiian Fishes. Tokyo: Keigaku.

Yamaguti, S. (1971). Synopsis of Digenetic Trematodes of Vertebrates. Tokyo: Keigaku.

Yochelson, E. L. (1979). Early radiation of Mollusca and mollusc-like groups. In The Origin of Major Invertebrate Groups, Systematics Association, Special vol. 12, (ed. House, M. R.), pp. 325–58. London and New York: Academic Press.

The following seven points highlight the classification of Platyhelminthes: 1. Polystoma Classification 2. Fasciola Classification 3. Schistosoma Classification 4. Paramphistomum Classification 5. Echinococcus Granulosus Classification 6. Dipylidium caninum Classification 7. Cotugnia Classification.

Type # 1. Polystoma Classification:

Phylum: Platyhelminthes Aceolomate, organ grade and flatworm.

Class: Trematoda Ecto-or endoparasitic; body well without epidermis and cilia, well-development suckers present.

Order: Monogenea Oral sucker weak or absent; anterior end with a pair of adhesive structure; posterior end with an adhesive disc with hooks. Life cycle is completed on one host only.

Genus: polystoma

Comments:

1. Polystoma (Fig. 5.5) is leaf-like and dorso-ventrally flattened.

2. Anterior end is provided with a weak oral sucker.

3. Mouth is surrounded by the oral sucker.

4. Pharynx is muscular and leads into the bifurcated intestine which finally unit posteriorly. Both the branches of intestine also join each other by transverse connections.

5. Posterior disc or opisthaptor is expanded and contains three pairs of large suckers and 2 or 3 hooks.

6. Hermaphroditic Male reproductive organs consist of single testis, a vas deferens and a penis. Female system comprises single ovary, oviduct, two vaginae and longitudinal vitelline ducts.

7. Breeding season starts in spring.

Habit and habitat:

Polystoma is found in the urinary bladder of frogs and turtles.

Type # 2. Fasciola Classification:

Phylum: Platyhelminthes Aceolomate, organ grade and flatworm.

Class: Trematoda Ecto-or-endoparasitic; body wall without epidermis and cilia, well-developed suckers present.

Order: Monogenea Endoparasitic, mostly with two suckers without hooks. Life cycle is completed on two hosts.

Genus: Fasciola

Species: Hepatica

Comments:

1. Fasciola hepatica (Fig. 5.6) is commonly known a sliver fluke.

2. Body is leaf-like, dorso-ventrally flattened, measures 25-30 mm in length and 4-5 mm in breadth.

3. Anterior end is small and conical, while the posterior end is large more rounded in front than behind.

4. Anoral sucker’ is situated apically and a large highly muscular ventral sucker(acetabulum) is located a little posterior to the oral sucker.

5. Mouth is situated at the anterior end and is surrounded by the oral sucker.

6. Digestive system is simple,pharynx is muscular, oesophagus short and branched and diverticulitis intestine.

7. Between the oral and ventral sucker is a median genital pore through which pass eggs to the exterior.

8. Excretory pore lies at the extreme posterior end of the body.

9. Hermaphroditic Male system consists of testes, vasa deferentia, seminal vesicles, ejaculatory duct and penis, while female system comprises of ovary, uterus and vitelline glands.

10. Life cycle is complicated includes an intermediate host. Limnaea (a mollusc-fresh water snail).

11. Liver fluke causes a disease known asliver rot.

Habit and habitat:

Fasciola hepatica is found as an endoparasite in the bile ducts or liver of sheep.

Type # 3. Schistosoma Classification:

Phylum: Platyhelminthes Characters same as those of Fasciola.

Class: Trematoda …….. –do-

Order: Digenea

Genus: Schistosoma

Comments:

1. Schistosoma (Fig. 5.7) is commonly called the blood fluke.

2. Body long, slender in form and greyish or pinkish in colour.

3. Sexes are completely separate.

4. Male is usually 8 to 16 mm in length, has a cylindrical stout and flattened body.

5. Female is longer than male, usually 15 to 20 mm in length, has a more slender delicate cylindrical body.

6. Males carry females permanently in their gynecophoric canals formed by the in-folding of the ventral body wall.

7. Life cycle includes a secondary host which is Bulinus or Planorbis (a mollusc, fresh water snail).

8. Its infection causes a disease called schistosomiasis.

9. Its 3 species are: S. haematobium, S. mansoni and S. japonicum.

Distribution:

Schistosomes have been reported from Africa (particularly form Egypt), West Indies, South America, Japan, China, Celebes and Philippines.

Type # 4. Paramphistomum Classification:

Phylum: Platyhelminthes

Class: Trematoda Characters same as those of Fasciola.

Order: Digenea

Genus: Paramphistomum

Comments:

1. Paramphistomum (Fig. 5.8) is small, triangular in shape and dorsoventrally flattened.

Fig. 5.8. Paramphistomum:

2. The oral sucker is absent.

3. The ventral sucker is large, muscular and situated posteriorly. It acts as an adhesive organ.

4. It is called amphistome parasite, because acetabulum is large and is found near posterior end of the body.

5. The intestine is forked and un-branched.

6. The male system comprises of two testes with tandem arrangement, sperm ducts, seminal vesicle and cirrus.

7. The female system comprises of ovary, ootype, vitellaria and folded uterus.

8. The genital antrum lies just beneath the fork of intestine.

9. The eggs are large.

10. The lymphatic system is present.

Habit and habitat:

Paramphistomum is an endoparasite in the remen of sheep, goat, deer, cattle, etc.

Distribution:

It is reported from India, Sri Lanka, Burma, other parts of Asia, Europe and U.S.A.

Type # 5. Echinococcus Granulosus Classification:

Phylum: Platyhelminthes Cestoda

Subclass: Eucestoda

Order: Taenioidea

Family: Taeniidae

Genus: Schistosoma

Species: Gramulosus

Comments:

1. Echinococcus granulosus is commonly called dog tapeworm.

2. The worm is only 2-8 mm in length and consists of ascolex, neck and three or four successive large segments (proglottids).

3. The scolex or head bears four suckers and a protrusiblerostellum provided with double rows of 30 to 36 hooks.

4. Proglottids are usually three, first proglottis is generally immature, second proglottis is mature, while the third is large and gravid.

5. It is hermaphrodite. Male reproductive system consists of spherical testes, vas deferens and cirrus. Female reproductive system comprises of ovaries, oviduct, vitellaria, ootype, uterus and vagina.

6. Its gravid proglottis is elongated containing branched uterus with onchospheres.

7. Its infection in man occurs by playing with infected dogs and sometimes the infective onchosphere also reach to man’s body along with food or drink.

8. Hydatid cyst or larval stage occurs in man and other domestic animals, e.g., monkey and cattle.

9. Echinococcus is cosmopolitan in distribution specially in cattle and sheep raising areas.

10. Its hydatid cysts are harmful to man; the cystic fluid is toxic and causes vomiting, diarrhoea, abdominal pain, eosinophilia, etc.

Habit and habitat:

Echinococcus granulosus is an endoparasite in the intestine of dogs, cats and foxes (primary hosts) etc. Its secondary hosts are man, rabbits, kangaroos, sheep and cattle.

Distribution:

Cosmopolitan, especially found in sheep and cattle raising areas. Its infection has been reported from Australia, Japan, India, New Zealand, China and U.S.A.

Type # 6. Dipylidium caninum Classification:

Phylum: Platyhelminthes

Class: Cestoda Characters same as those of Taenia solium.

Subclass: Eucestoda

Order: Taenioidea

Family: Dilepididae Rostellum retractile with one or more circlets of hooks.

Genus: Dipylidium

Species: caninum

Comments:

1. Dipylidium caninum (Fig. 5.10) is commonly called dog tapeworm.

2. It is commonly found in pet dogs and cats but rarely in children.

3. It measures 25 cm in length with about 150 proglottids.

4. Its rostellum is muscular, retractile and bears rose-thorn hooks arranged in four transverse circular rows.

5. Its scolex contains four suckers.

6. Its mature proglottids are long and slender with double sets or hermaphrodite reproductive organs and a genital pore on each lateral margin.

7. Testes numerous scattered throughout proglottid.

8. Uterus reticulate which breaks into uterine capsules containing about 30 embryos or less.

9. Dog-louse and dog-flea are secondary hosts in which systicercoids develop.

Type # 7. Cotugnia Classification:

Phylum: Platyhelminthes

Class: Cestoda

Subclass: Eucestoda

Order: Taenioidea

Family: Davaineidae

Genus: Cotugnia

Comments:

1. Cotugnia is medium-sixed davaineid tapeworm parasitizing pigeon, fowl, duck, peacock, parrot, crow, kite, etc.

2. Tostellum simple with a large number of hammer-shaped hooks arranged in two rows.

3. Scolex bears four spinose suckers.

4. Proglottids bear double set of hermaphrodite reproductive organs (the only davaineid with double set of reproductive organs).

5. Proglottids very short, broader than long except the last ones which are longer than broad.

6. Testes numerous, lie in extravascular field, may or may not cross excretory vessels.

7. Ovaries medially placed.

8. Genital ducts dorsal to excretory vessels and nerve stem.

0 Thoughts to “Amphistomes Classification Essay

Leave a comment

L'indirizzo email non verrà pubblicato. I campi obbligatori sono contrassegnati *