160 PARASITES OF THE DOMESTIC ANIMALS 



Taenia saginata. Host, man. P. 195. 



Larva, Cysticercus bovis. Host, ox. P. 195. 

 T. solium. Host, man. P. 199. 



Larva, Cysticercus cellulosse. Host, hog, etc. P. 199. 

 Family (b) Diphyllobothriidse. P. 185. 

 Genus and Species: 



Diphyllobothrium latum. Hosts, man, dog, cat. P. 185. 

 Larva, a plerocercoid. Host, fish. P. 185. 



Family I. Fasciolid^ 



1. Fasciola hepatica (Distomum hepaticum). The Liver Fluke 



(Fig. 87). Trematoda (p. 156). — ^The body is flattened, pale brown in 

 color, oval in shape, and broadest in front, where it is terminated by 

 a conical process bearing at its apex the oral sucker which surrounds 

 the mouth. A larger ventral sucker is situated about 3 mm. behind 

 the oral. The cuticle is studded with minute spines directed back- 

 ward. The bifurcations of the ahmentary tract have ramifying 

 branches. The vulva is situated beside the male opening or a little 

 behind it. 



Length, 20-30 mm. {%-\H inches); width, 10-13 mm. (73-3^ an 

 inch). 



The eggs are brown or greenish-yellow, provided with an operculum 

 a,t one end. They are oval and 130-145 microns in length. 



2. Dicrocoelium lanceatum (Fasciola lanceolata). The Small Liver 

 Fluke (Fig. 87). Trematoda (p. 156).— The body is slender and 

 lancet-shaped, mottled brown by contained ova. The integument is 

 smooth and semi-transparent. The intestine has two nonramifying 

 branches. 



Length, 4-9 mm. (3/16-3/8 of an inch); width, 2.5 mm. (1/8 of an 

 inch) . 



The eggs are oval, brownish in color, 37-40 microns in length, and 

 provided with an operculum. 



3. Fasciola magna (F. americana, Distomum americanum, D. mag- 

 num). The Large American Liver Fluke (Fig. 87). Trematoda 

 (p. 156). — Similar to F. hepatica, but larger, measuring 25-33 mm. 

 (1-13^ inches) in length and 12-17 mm. (J^-^) of an inch in 

 width. 



Life History of Fasciola hepatica. — The eggs leave the uterus be- 

 fore the beginning of embryonic development and pass to the outer 

 world by way of the bile ducts and intestines. In heavy infestation 

 enormous numbers may be passed by a single host animal, one mature 

 fluke producing in the neighborhood of one hundred thousand eggs. 



