TEEMATODES 183 



seminis present; the uterus is a long tube, containing eggs; yolk glands 

 either branched or compact: parasitic as adults in the intestine and 

 other hollow organs of vertebrates; over 1,700 species, the family rela- 

 tionships of which are as yet more or less obscure. 

 Key to the genera of Distomata here described: 



d Hermaphroditic distomes. 

 &! Ovary in front of testes. 

 Ci Uterus does not extend back of testes. 

 di Intestinal trunks with lateral projections ; ovary and testes branched. 



1. FASCIOLA 

 <f a Intestinal trunks without lateral projections. 



6i Genital pore back of acetabulum 2. PABAGONIMUS 



e a Genital pore not back of acetabulum. 

 /! Mouth surrounded by spines. 



& A single row of spines 3. ECHINOSTOMA 



02 A double row of spines 4. STEPHANOCHASMUS 



/ 2 No spines around the mouth. 



X Excretory vesicle winds between the testes 5. AMPHIMEBUS 



02 Excretory vesicle does not wind thus 6. AZYGIA 



C 2 Uterus extends back of testes. 



di Mouth surrounded by 6 long papillae 7. BUNODEEA 



d s No such papillae. 

 e^ Intestinal trunks reach to about the middle of the body. 



/! Yolk glands branched and in middle area of body 8. RENIFEB 



/ 2 Yolk glands compact and at end of body 13. MICBOPHALLUS 



2 Intestinal trunks reach the rear end of body. 

 A Genital pore near front end of body. 

 0! Genital pore near pharynx ; in lungs of frogs and toads. 



9. PNEUMONO3CES 



02 Genital pore in front of oral sucker , ... 10. CEPHALOGONIMUS 



f s Genital pore near acetabulum ; yolk glands compact and lobate. 



0! Testes 2 in number 11. GOBGODEBINA 



02 Testes 9 in number 12. GOBGODEBA 



6 2 Ovary behind testes. 



e?i Hinder end of body not telescopic 14. HALIPEGUS 



C 2 Hinder end telescopic 15. HEMIUBUS 



6 3 Ovary between the testes 16. CLINOSTOMUM 



a a Unisexual distomes 17. SCHISTOSOMA 



1. FASCIOLA L. Body broad and leaf-like, covered with minute 

 spines and with a short conical anterior end at the base of which is the 

 acetabulum; intestine, excretory vesicles, and genital glands richly 

 branched; genital pore in front of acetabulum: in liver of herbivores; 

 about 4 species. 



F. hepatica L. Liverfluke. Length 18 to 50 mm.; width 4 to 13 

 mm.; conical anterior end distinctly set off; body thin and flat: in the 

 gall passages of cattle, sheep, man, and other animals, causing 

 liver rot, which is often very fatal to herds ; intermediate host a snail of 

 the genus Lymnaea ; cosmopolitan, but rare in America, except in southern 

 Texas, in Florida, and a few other places. 



