530 



FRESH-WATER BIOLOGY 



49 (50) With anterior end bent dorsad. No intestinal cecum present. 



Cucullanus O. F. Miiller 1777. 

 Anterior end flexed dorsad 60 to 90 degrees. Spicules with accessory piece. Ovary double. 



Representative species in North America. 



Cucullanus clitellarius Ward and Magath. 



Body uniform in diameter except for clitellar-like swelling i mm. long, and 1.5 mm. from 

 anterior tip. On each oral margin three small papillae. Male 10 mm. long by 0.38 mm. 

 broad. Esophagus 1.45 by 0.12 to 0.22 mm. Spicules gouge-shaped, 1.62 by 0.035 mm.; 

 accessory piece dagger-shaped, 0.06 by 0.015 mm. Two small preanal papillae; 4 pairs of 

 postanals. Females 12 to 17 by 0.5 mm. Esophagus 1.6 by 0.13 to 0.32 mm. Vulva two- 

 thirds of length from anterior end. Uterus and ovary double. Ova 63 by 46 /*. 

 In intestine of lake sturgeon; Lake St. Clair. 



50 (49) Anterior end straight; well-developed intestinal cecum present. 



Dacnitoides Ward and Magath. 



Much like Cwullanus except that anterior tip is not flexed, an accessory 

 piece is lacking and only a single ovary is developed. The intestine pos- 

 sesses a prominent cecum extending anteriad to the nerve ring. 



Representative species in North America. 



Dacnitoides cotylophora Ward and Magath. 



Male 4 to 6 mm. long, 0.2 mm. broad. Each lateral valve with anterior 

 marginal cuticular thickening bearing 3 papillae. Esophagus 0.5 to 0.6 by 

 0.06 to 0.12 mm. Boundary between esophageal regions at nerve ring. 

 Spicules 0.89 by 0.005 mm. Caudal papillae: one pair on anterior margin 

 of sucker, four pairs between sucker and anus, a single medial papilla just 

 in front of anus and four pairs postanal. 



Female 4 to 5.5 mm. long, 0.28 mm. broad. Anus 0.14 from posterior 

 tip with 4 slender spines midway between. Vulva one-eighth of total length 

 behind center of body. Posterior uterine branch has no ovary. Ova 65 

 by 40 n. 



In intestine of yellow perch and wall-eyed pike; Lake St. Clair. 



FIG. 823a. Dacnitoides cotylophora. Head of female, showing oral armature, 

 esophageal regions, intestine, cecum, and anterior coils of ovary. X 57. (After 

 Ward and Magath.) 



51 (16) Stout bodied forms with conspicuous lips 52 



52 (55) Two heavy lips. Body covered on anterior region at least with 



dentate or spinous plates. 



Family GNATHOSTOMIDAE Railliet 1893. 



Body covered in whole or part by circles of dentate cuticular plates. Anterior tip enlarged, 

 provided with simple spines, separated by nuchal constriction. Two large fleshy lips. 

 Esophagus large, muscular. Vulva behind middle of body. Two equal spicules. No bursa. 

 In male two pairs of preanal papillae and two postanals. 



Type genus Gnathostoma Owen 1836 . . 53 



Entire body or anterior end covered with abundant spines, often many pointed. Head 

 separated by circular constriction, with circles of simple spines. Two large, fleshy lips. Spic- 

 ules 2, unequal; vulva behind center of body. Male with two pairs of postanals. 

 Two species reported from North American. 



53 (54) Anterior plates palmate with eight spines each. 



Gnathostoma horridum (Leidy) 1856. 

 Female 66 mm. long, 3 mm. broad. Male unknown. 



Taken from stomach of Alligator mississippiensis in Georgia and originally described by 

 Leidy as Cheiracanthus horridus. 



54 (53) Anterior plates tridentate. . . . Gnathostoma sociale (Leidy) 1858. 

 Female 30 mm. long, 1.5 mm. broad. Male 24 mm. long, i mm. broad. 



Taken from stomach of mink (Putorius vision) in Philadelphia and originally described by 

 Leidy as Cheiracardhus socialis. 



