EXAMINATION OF HELMINTHES 141 



lungs, especially in cattle. In the gall-ducts of cats and dogs, the 

 fluke of the cat (Opisthorchis felineus) is found, together with a very 

 small variety, Metorchis truncatus (Kud.) (fig. 63), which does not 

 exceed 2 mm. in length. Cats also harbour M. albidus (Braun), the 

 length of which varies from 2'5 to 3*5 mm. 1 The liver-fluke is 

 pathogenic to sheep, the cat-fluke to cats and dogs. 



Paramphistomum cervi (= Amphistomum conicum, Kud.), occurs in 

 the paunch of cattle, sheep, and goats. The worm is about 1 cm. in 

 length, and is attached to the mucous membrane between the papillae 

 by its hinder end. It is prepared by the methods described above. 



The Trematode fauna of domestic birds is somewhat more 

 numerous. The following Echinostomes occur in the intestine of 

 geese, ducks, and hens : Echinostomum conoideum (Bloch) = Dis- 

 tomum oxyceplialum, Bud. ; E. revolutum (Frol.) = D. echinatum, 

 Bud. ; and E. recurvatum (v. Lstw.). These varieties are charac- 

 terized by the possession of a collar, studded with hooks, at the 

 anterior end. Prosthogonimus pellucidus, which is found in the 

 terminal portion of the intestine of hens, is characterized by the 

 position of the genital opening, which is situated anteriorly, close to 

 the oral sucker. This parasite frequently penetrates to the oviduct 

 of its host, becomes enclosed in the eggs, and may be found in them 

 after they are deposited. 2 Of the Monostomatidae, Notocotyle verru- 

 cosa (Frol.), which grows to a length of 5 to 6 mm., is frequently 

 met with in the caecum of geese and ducks ; while grazing geese 

 harbour Monostomum arcuatum (Brds.), a parasite 20 mm. in 

 length, which is found in the cellula infraorbitalis. 



The Development of Digenetic Trematodes. The development of 

 the ova, and of the miracidia from the ova, has been already described. 

 Where the artificial infection of molluscs is not possible, indigenous 

 fresh-water snails and mussels should be examined during the summer 

 months, for cercariae, rediae and sporocysts. The mollusc most 

 frequently affected is Limnceus stagnalis, which lives among water 

 plants in stagnant ponds and glides over the surface of the water 

 with dependant body. There are other varieties of the same or of 

 allied genera (Planorbis, Paludina, Bithynia, &c.), many of which 

 live in quiet eddies of running water, where sporocysts are also to 

 be found. The snails should be put alive into small glass vessels 

 with sufficient water; the vessels should be covered and allowed 

 to stand. If infected individuals are among the snails, the cercariae 

 will emerge and will be seen macroscopically, after about twenty-four 



1 Braun, Centralb.f. Bakt. und Paras., vol. xiv, 1893, p. 881. 



2 Braun, Centralb. f. Bakt, Paras, und Inf., part 1, vol. xxix, 1901, p. 12; and 

 Zool JaJirb. Syst., vol. xvi, 1902, p. 67. 



