194 



PLATHELMINTHES 



Fig. 314 — Schistocephalus gasterostei. A, forward 



end (Linton) ; B, fish containing the larval 



worm (CV.'nbridge Natural History). 



S. gasterostei (Fabricius) (Fig. 314). Length up to 30 cm.: in 

 Castcrosteus and otlior fish and also the frog as a lai'va, and in water birds 

 as adult. 



Subfamily 2. DIPHYLLOBOTHRIINAE. 



Seolex without hooks and with either 2 small suckers or highly modi- 

 fied suckers; segmentation distinct; cirrus and vagina open into a 



genital cloaca, the pore of 

 which is ventral and in 

 front of the uterine pore: 

 6 genera; in higher verte- 

 brates. 



1. DlPHYLLOBOTHRITJM 



Cobbold (Bothriocephalus 

 Rudolphi; Dihothriocepha- 

 lus Liihe). Seolex flattened laterally with 2 deep slit-like suckers; strobila 

 long; uterus a long tube coiled zigzag: over 50 species; in carnivorous 

 mammals and water birds. 



D. latum (L.) (Fig. 315). 

 Length up to 9 m., with several 

 thousand segments; onchosphere 

 ciliated and free-swimming: larva a 

 plerocereoid 30 mm. long found in 

 the perch and many other fishes; 

 adult worm in man, also in the cat 

 _ and dog, and com- 



mon in certain locali- 

 ties, especially where 

 fish is much eaten : 

 in this eountiy rare. 



Subfamily 3. CYATHOCEPHALINAE. 



Seolex usually with a single terminal sucker; outer 

 segmentation indistinct or wanting; genital pores either 

 ventral or dorsal or both: 1 genus. 



Cyathocephalus Kessler. With the characters of 

 the subfamily : 1 species. 



C. truncatus (Pallas) (Fig. 316). Length up to 20 

 mm.; with about 6 segments: in the pyloric coeca of the 

 whitefish. 



Family 2. PTYCHOBOTHRIIDAE. 

 Seolex without hooks, with 2 suckers more or less developed, each 

 of which may be converted into a pocket by the partial fusion of its 



Fig. 315 — Diphyllohothrium latum 

 (Leuckart). A, anterior end, showing 

 suckers ; B, mature segment. 1, yolk 

 gland ; 2, birth pore ; 3, uterus ; 4, 

 ovary ; 5, excretory canal ; 6, nerve ; 

 7, testes ; 8, vaginal pore ; 9, male geni- 

 tal pore (cirrus) ; 10, uterine pore. 



;'«' 



