PARASITIC FLATWORMS 



407 



146 (147) Cirrus sac does not extend posteriad beyond acetabulum. 



Lechriorchis Stafford 1905. 



Distomes of submoderate size oval, narrower behind, ventral sucker 

 much larger than oral (?), one-third body length from anterior end. Skin 

 spinous. Pharynx and esophagus present; crura extend to [posterior 

 margin of ?] testes, two-thirds length of body. Testes large, nearly 

 symmetrical, almost in contact. Cirrus sac large, dorsal and anterior to 

 acetabulum on right side. Genital pore at fork of intestine. Ovary 

 small, spherical, at the end of cirrus sac, on right posterior margin of 

 acetabulum. Uterus extends directly posteriad to end of body and then 

 anteriad, ascending limb greatly expanded. Vitellaria [lateral ?], nearly 

 entire length of ceca. Eggs dark brown. 



Two species from North America; type L. primus in lung of garter 

 snake. The only well-described species is one which Stafford says be- 

 longs here; it is L. elongatus { = Renifer elongatus Pratt) in mouth of 

 Heterodon platyrhinus. Renifer megasorckis Crow 1913 from the uterus 

 of Natrix rhombifera may belong here. 



Fig. 707. Lechriorchis elongatus. Dorsal view. X 15. (After Pratt.) 



147 (146) Cirrus sac extends posteriad beyond posterior margin of acetab- 



ulum. . . . Zeugorchis Stafford 1905. 



Small, elongate elliptical distomes with subterminal oral sucker and spinous skin. Ace- 

 tabulum near center of body. Pharynx and esophagus present, crura extend to testes only. 

 Testes oval, lateral, separated. Cirrus sac large, dorsal, extending posterior to acetabulum. 

 Genital pore in fork of intestine. Ovary small, spherical, at end of cirrus sac. Uterus with 

 descending and ascending limbs, reaches to posterior end; eggs very numerous. Vitellaria 

 lateral along crura, but also covering same and approaching median Une dorsally. Excretory 

 bladder median, large, with evident lateral branches. 



Single North American form, type species. 



Zeugorchis aequatus Stafford 1905. 

 In esophagus and stomach of garter snake; Canada. This form is very inadequately de- 

 scribed and its position is somewhat a matter of conjecture. Odhner beUeves it should be 

 placed in this subfamily. 



148 (65) Ovary posterior to one or both testes 149 



149 (152) Ovary posterior to both testes. 150 



150 (151) Uterine coils anterior to ovary, between it and acetabulum; testes 



small, oblique, nearly symmetrical, widely separated from 

 each other, lateral near acetabulum. . . . Leuceruthrus. 

 For description and figure consult 87 (86) in this key. 



151 (150) Uterine coils posterior to ovary, between it and posterior end; 



testes large, oblique or nearly median, forming with acetabu- 

 lum and ovary almost a continuous median series. 



Family Dicrocoeliidae Braun 191 5. 



Elongate, flattened, transparent distomes of moderate size with weak suckers and poorly 

 developed musculature. Acetabulum near anterior end. Intestinal crura do not reach pos- 

 terior end. Excretory bladder tubular, reaching anteriad to center of body. Genital pore 

 median, between suckers, near fork of intestine. Cirrus sac small, cirrus conspicuous. Germ 

 glands postacetabular with testes symmetrical, oblique, in median series in front of ovary. 

 Vitellaria occupy central region of body mostly outside of intestinal crura. Uterus long with 

 descending and ascending branches in transverse coils, mostly filling area behind ovary. Eggs 

 moderate in size, very abundant, thick shelled, dark brown. 



Parasitic chiefly in gall ducts of Anmiota. 



Type genus Dicrocoelium Dujardin 1845. 



Body tapering towards both ends, more anteriad. Testes oblique, close together. Vitel- 

 laria lateral, symmetrical, small. Genital pore with cirrus sac between ventral sucker and 

 fork of intestine. Uterus prominent, filling entire body behind germ glands which he between 

 acetabulum and center of body. 



