TREMATODES 



187 



Fig. 306 Microphallus 

 opacus (Ward). 



References 

 as in Fig. 293. 



H. occidualis Stafford. Body 6 mm. long; 1.5 mm. wide; testes in 

 oblique plane near acetabulum: in the mouth of frogs. 



15. HEMITJRUS Rudolphi. Small, cylindrical worms, the hinder end 

 of whose bodies forms an appendix which can 



be invaginated; cuticula transversely striped; 

 3 7 olk glands compact, behind ovary, which is just 

 behind the testes: in fish. 



H. appendiculatus (Rud.). Appendix from 

 a third to twice the length of the body; acetabu- 

 lum much larger than oral sucker; yolk glands 

 spherical; 6 mm. long: in digestive tube of her- 

 ring and other marine fish; intermediate host 

 usually copepods. 



16. CLINOSTOMTTM Leidy. Elongated worms 

 with mouth surrounded by a circular ridge; ovary 

 between the testes in middle of body; intestine 

 without pharynx and with side projections: in 

 mouth of birds; about 10 species. 



C. marginatum (Rudolphi) (Fig. 307). Body 6 to 10 mm. long; 

 1 to 2 mm. wide; yolk glands voluminous: in Ardea and other birds; 

 intermediate host, the / 



sunfish and other fishes. 



17. SCHISTOSOMA 



Weinland. Sexes sepa- 

 rate ; acetabulum near 

 front end; male is larger than the 

 female and has a deep groove in 

 its ventral side in which the fili- 

 form female lies: several species, 

 in blood of mammals in tropical 

 countries. 



S. haematobium (Bilharz) 

 (Fig. 308). Body cylindrical; 

 length of male 14 mm.; length of 

 female 20 mm.: in the blood of 

 man, chiefly in Africa, occasionally 

 in this country. 



-IL 



Fig. 307 



Clinostomum 



marginatum 



(Osborn). 



References 



as in Fig. 293. 



DIVISION 4. HOLOSTOMATA. 



Fig. 308 

 Schistosoma 

 hcematobium 



(Looss). 

 1, oral sucker ; 



2, acetabulum ; 



3, male individ- 

 ual ; 4, female 

 individual. 



Digenetic trematodes with an oral sucker and an acetabulum, and 

 in addition a large variously constructed adhesive ventral disc or pro- 



