PARASITIC FLATWORMS 



389 





70 (73) Large flattened distomes; ovary and testes both highly branched; 

 uterus median, a short series of transverse coils. 



Family FASCIOLIDAE Railliet 1895. 



Large distomes with muscular, more or less broad and flattened leaf-shaped body. Ventral 

 sucker powerful, close to anterior end. Intestinal crura extend to posteror end. Excretory 

 bladder tubular, extends anteriad beyond testes. Genital pore median, at anterior margin 

 of acetabulum. Cirrus and cirrus sac well developed. Ovary lateral, in front of acetabulum, 

 testes symmetrical, postacetabular. Vitellaria extensive, reaching posterior end. Uterus 

 short, in condensed coil, entirely preovarian. Eggs very large, thin shelled, in moderate num- 

 bers. Development with alternation of hosts and generations. 



Parasites in intestine and gall ducts of Mammalia. 



Reported in North America. 



Subfamily FASCIOLINAE Stiles and Hassall 1898 . . 71 



71 (72) Anterior tip distinctly set off from main body; vitellaria both dorsal 

 > and ventral of intestinal branches. Fasciola Linnaeus 1758. 



Very large distomes with leaf-shaped body having so-called "cephalic 

 cone" set off at anterior end, and pointed posterior end. Skin spinous. 

 Acetabulum large, at junction of cephalic cone and main body. Esophagus 

 short, with pharynx and prepharynx. Intestinal crura near median line, 

 extend to posterior end, provided on mesial aspect with short branches 

 and on outer side with long branches which again may be branched. 

 Uterus in front of acetabulum, forming a rosette. Vitellaria richly de- 

 veloped in lateral area, and in posterior region also on both surfaces of body. 



In the gall passages of herbivores, very rarely in man. 



Type species. . . . Fasciola hepatica Linnaeus 1758. 



An introduced species (F. hepatica} common in sheep and cattle in 

 limited regions; Long Island, N. Y., introduced from Texas, Gulf States, 

 California. The North American intermediate host is not known. Stiles 

 suspects Limnaea humttis Say. 



FIG. 675. Fasciola hepatica. X 3- (Original.) 



72 (71) No distinct anterior conical portion. Vitellaria ventral to intestinal 

 branches Fascioloides Ward. 



Body very, large, broad, thick, without separate anterior portion or cephalic cone, posterior 

 end bluntly rounded. Vitellaria confined to region ventral to intestinal branches. 



Type species. 



. . . Y' . . . Fascioloides magna (Bassi) 1875. 



In liver and lungs of North American herbivores both do- 

 mestic and wild; usually included in former genus. On the 

 advice of Odhner a new genus is made for the North American 

 form. First discovered in a European zoological garden para- 

 sitic in the wapiti, it is known to occur in many hosts and to 

 be widely distributed from Maine to California. It is espe- 

 cially abundant in parts of the South. Egg and embryo are 

 said by Stiles to agree with those of the last species. 



FIG. 676. Fascioloides magna. Intestinal crura and branches 

 drawn as solid black lines. Natural size. (Original.) 



Another genus, Fasciolopsis, common as a parasite of man 

 in some parts of the East, has been reported in North America 

 a few times as a human parasite. Apparently all these cases 

 have been imported and the parasite has not so far as known 

 gained a foothold on this continent. 



