390 



FRESH-WATER BIOLOGY 



73 (70) Distomes moderate in size, thick bodied; ovary and testes lobed 

 or coarsely branched; uterine coil chiefly lateral to acetab- 

 ulum Family TROGLOTREMATIDAE Odhner 1914. 



Distomes of small to moderate size with compressed body. Skin with spines in groups. 

 Ventral surface flat, dorsal arched. Musculature and suckers poorly developed. Intestinal 

 crura do not reach posterior end. Excretory bladder Y-shaped, or tubular. Genital pore 

 close to acetabulum. Cirrus sac lacking. Testes symmetrical, postacetabular. Ovary 

 dextral, immediately in front of testes, lobed or branched. Laurer's canal present. Vitel- 

 laria very extensive, covering dorsal surface save for narrow median strip. Uterus long, in 

 open loops, or shorter in tight coil; eggs in first case small, in second moderately large. 



Parasites of birds and carnivores, living usually by pairs in cyst-tike cavities. 



The monostome, Collyridum colei\(p. 384), is regarded by Odhner as properly a member of 

 this family. 



Only American genus Paragonimus M. Braun 1899. 



Body opaque, thick, nearly rounded in cross section. Skin 

 with spines. Pharynx almost spherical, crura wavy with irregular 

 walls. Testes lobed, symmetrical, in hindbody. Ovary lobed, 

 lateral, pretesticular, and postacetabular. Vitellaria extend en- 

 tire length of body, lateral and dorsal. Laurer's canal and 

 rudimentary receptaculum present. Uterus in coil, postacetabu- 

 lar, opposite ovary. Eggs large, thin-shelled, laid before cleav- 

 age begins. 



Encysted, in pairs usually, in lungs of mammals. 



Single American species. 



Paragonimus kellicotti Ward 1908. 



Parasitic in dog, cat, and pig. Ohio, Illinois, Wisconsin, 

 Minnesota, Kentucky. Confused in records with the human 

 lung fluke (P. westermanii Kerbert) which has been positively 

 determined in North America only in a few human cases, all of 

 which are probably imported from Asia. 



FIG. 677. Paragonimus kellicotti. Total preparation, ventral surface. 

 The yitellaria are represented on the left side and omitted on the other 

 side in order to show ovary, testis, vitelline ducts and intestine normally 

 obscured by them. X 38. a, egg from same specimen. X 150. 

 (After Ward and Hirsch.) 



74 (69) Ovary and testes entire or lobed but not dendritic . 75 



75 (82) Oral sucker surrounded by a reniform collar open ventrally and 



bearing a series of strong spines. 



Family ECHINOSTOMIDAE Looss 1902 .. 76 



Elongate distomes, very variable in size. Acetabulum powerful, close to anterior end. 

 Oral sucker small, weak or degenerate; anterior end surrounded laterally and dorsally by 

 skin fold or "collar" which carries large spines ("spikes") definite in number and arrange- 

 ment. "Corner spines" on ventro-median lobe usually differ from others, i.e., "marginal 

 spines." Skin in anterior region at least richly provided with fine dermal spines. Pharynx 

 and esophagus present; intestinal crura extend almost to posterior tip. Excretory bladder 

 Y-shaped with numerous lateral branches. Genital pore median, near acetabulum or between 

 it and fork of intestine. Cirrus and cirrus sac well developed. Germ glands postacetabular, 

 usually median; ovary pretesticular, sometimes lateral. Vitellaria lateral, well developed, 

 reaching posterior end. Uterus between ovary and acetabulum, with scanty lateral loops, 

 or none. Laurer's canal present, receptaculum seminis absent. Eggs large, thin shelled, not 

 numerous. Development with alternation of hosts and generations. For characteristic 

 cercariae see 224 (220) in this key. 



Parasites of intestine, rarely of gall ducts, in mammals and birds. 



76 (81) With well-developed oral sucker. Parasitic in intestine. ... 77 



77 (80) Anterior region not enlarged. Spines in a double row. .... 78 



