PARASITIC FLATWORMS 



393 



88 (85) Body flat, thin, transparent; no cirrus sac present. 



Family OPISTHORCHHDAE Luhe 1901 . . 89 



Elongate flattened transparent distomes with weak musculature. Suckers close together 

 and very weak. Intestinal crura reach fully or nearly to posterior end. Excretory bladder 

 Y-shaped with short branches and long stem. Genital pore close in front of acetabulum. No 

 cirrus or cirrus sac. Coiled seminal vesicle. Germ glands in series in posterior region, ovary 

 in front of testes. Vitellaria outside intestinal crura, moderately developed, not reaching 

 posterior end. Uterus long, preovarian, in transverse loops, mostly postacetabular. Eggs 

 very numerous, small, light yellowish brown in color. 



Parasites of gall passages of Amniota. 



An important parasite of man, Clonorchis sinensis, which belongs to this family has been 

 introduced several times into this continent but apparently has not gained a footing. 



89 (90) Neither uterine coils nor vitellaria extend anteriad beyond 



acetabulum Opisthorchis R. Blanchard 1895. 



Anterior end conical, posterior end broader. Main stem of excretory bladder S-shaped, 

 passing between testes, anterior forks of Y short. Vitellaria in groups. 



In gall ducts of mammals, birds, and (?) fishes. Young distomes encysted in skin and con- 

 nective tissues, especially subdermal tissue of fishes. 



Several species in North America; best known O. pseudofelineus Ward 1901 in the cat. 



FIG. 680. Opisthorchis pseudofelineus. From liver of cat. X 5- (Criginal.) 



90 (89) Uterine coils and vitellaria both in part anterior to acetabulum. 



Metorchis Looss 1899. 



Small to moderate sized distomes with short, compressed body tapering anteriad. Skin 

 spinous. Testes slightly Ipbed, nearly symmetrical. Coils of uterus compact, extending clearly 

 over crura to margins. Vitellaria compact, extending anterior to acetabulum. 



A single American species M. complexus (Stiles and Hassall) from the liver of cat. New 

 York, Maryland, District of Columbia. Peculiar in extent and arrangement of vitellaria and in 

 position of testes. May need to be transferred to a new genus when its structure has been 

 worked out. 



FIG. 68 1. Metorchis complexus. Magnified. (After Stiles and Hassall.) 



91 (84) Ovary anterior, near acetabulum, separated from one or both testes 

 by coils of ascending and descending rami of uterus. 



Subfamily TELORCHIINAE Looss 1899 . . 92 



Small to middle sized distomes with slender, elongate, spinous, somewhat flattened body. 

 Anterior region very mobile; posterior region stable. Acetabulum small, in anterior region. 

 Pharynx present, esophagus variable, crura long. Testes tandem, both in posterior end or 

 one there and the other not far behind ovary. Laurer's canal and receptaculum seminis pres- 

 ent. Vitellaria lateral, elongate, outside intestinal crura. Uterus in coils or loops between 

 ovary and testes or when one testis is near ovary, between ovary and posterior testis. Eggs 

 numerous, small. 



In the intestine of reptiles. 



