PARASITIC FLATWORMS 



405 



138 (131) Vesicula seminalis at inner end of cirrus sac, continued to outer 

 end by long, tubular pars prostatica. 



Styphlodora Looss 1899. 



Body somewhat attenuated anteriad, but broadened 

 posteriorly, with rounded ends. Skin covered with fine 

 spines. Pharynx and esophagus present; crura do not 

 reach posterior end. Genital pore median, preacetabular. 

 Cirrus sac encloses coiled vesicula seminalis. Cirrus pow- 

 erful. Testes oblique, close together in center of body. 

 Vitellaria poorly developed. Receptaculum seminis pres- 

 ent, but small. Uterus intercecal, but spreading to margin 

 beyond ends of crura. Eggs numerous. 



In intestine of reptiles. 



One North American form described by Goldberger as 

 Styphlodora bascaniensis from the liver (?) of Bascanion 

 constrictor, Virginia, is a doubtful member of this genus. 



FIG. 703. Styphlodora bascaniensis. Ventral view. 

 (After Goldberger.) 



Magnified. 



139 (130) No receptaculum seminis, intestinal crura half to three-fourths 



body length, at least never reaching posterior end. 



Subfamily RENIFERINAE Pratt 1902 . . 140 



Crura of medium length, reaching beyond center of body but not into posterior tip. In 

 every case an open space or uterine coils intervene between the crura and posterior end of 

 body. 



No receptaculum seminis. 



Testes at ends of crura, more or less symmetrical. 



In mouth, air passages, lungs, esophagus and stomach of snakes. 



A group clearly worked out and defined by Odhner, richly represented in North America 

 where occur five out of the seven genera already described. 



140 (141) Genital pore marginal or nearly so Renifer Pratt 1902. 



Small distomes with elliptical, ventrally flattened body covered with 

 fine spines. Suckers moderately developed; acetabulum larger, anterior 

 to middle. Mouth subterminal; pharynx present; esophagus short; in- 

 testinal ceca reach beyond acetabulum, about to center of body. Ex- 

 cretory vessel Y-shaped. Genital pore marginal, about level of fork of 

 intestine. Testes both symmetrical just behind center of body near 

 ovary which is lateral at right posterior margin of acetabulum. Cirrus 

 sac large, reaching to or beyond acetabulum with convoluted seminal 

 vesicle. Vitellaria submoderate in size, lateral, in central third of body. 

 Uterus with descending and ascending limb, passing between testes nearly 

 to posterior tip; capacity provided by increase in breadth of tube and not 

 by extension in length and formation of coils. 



Representative American species. 



Renifer ellipticus Pratt 1903. 



Mouth and air passages of Heterodon platyrhinus. Only one certain 

 North American species, R. ellipticus Pratt 1903, type of the genus. 



FIG. 704. Renifer ellipticus. Ventral view. X 15. (After Pratt.) 



141 (140) Genital pore median or nearly so 142 



