5^8 



FRESH-WATER BIOLOGY 



female, o.i in male. Vulva one-fourth total length from caudal tip. Spicules two, large, 

 heavy, unequal. Ova 41 by 24 m, thick-walled. 

 In intestine of black crappie, sheepshead, and white bass at Fairport, Iowa. Abundant. 



Fig. 821. Spiniiectus gracilis. Anterior end of female. X 220. (After Ward and Magatb.) 



41 (28) Posterior end in female modified to form a sort of sucker by which 

 the parasite is attached to the stomach wall. 



Hedruris Nitzsch 182 1. 



Head with 4 lips: 2 lateral, slender, each with 2 papillae; 2 median, thinner, overlapping 

 laterals almost completely. Vulva near anus. Tail of female modified to form with included 

 spine, the caudal tip, an adhesive organ or sucker. Eggs elliptical, with lid-like areas at both 

 pointed poles, contain developed embryos. Male spirally wound around female. Tail strongly 

 compressed laterally: 6 pairs postanal papillae, i pair just preanal. Spicules 2, similar, very 

 short, apparently grown together. 



Type species. 



Hedruris androphora Nitzsch 1821. 



Reported from AmUystoma mexicana and Nanemys guttata by Stiles and Hassall. The form 

 described by Leidy in 1851 as Synpleda pendula certainly belongs in this genus if not in this 

 species. 



Also recorded 



Hedruris siredonis Baird 1858. 



In British Museum collection. From "stomach of Siredon mexicanus from Mexico." Male 

 not found. 



42 (27) Anterior end provided with heavy, lateral, valve-shaped lips. 



43 



43 (48) Lips red or brown, very conspicuous. Esophagus with two well 

 differentiated, distinctly separated regions. No preanal 

 sucker in male. 



Family Camallanidae RaiUiet and Henry 1915 . . 44 



Body nearly cylindrical, with heavy oral armature having the appearance of a bivalve shell, 

 which is really 2 thick, lateral, valve-like lips probably functioning as jaws and not a buccal cap- 

 sule. Each valve marked by longitudinal ridges terminating at the inner margin of the mouth 

 in minute teeth. Mouth an elongated oval; inner opening of oral cavity to esophagus round, 

 encircled by heavy basal ring of chitin. Several (2 to 4) heavy chitinous rods diverge from 

 common center at each side of capsule along sides of body beneath cuticula, forming a fork 

 or "trident." 



Esophagus bipartite, anterior region muscular, club-shaped; posterior dark, granular (gland- 

 ular?) ; valve to intestine. 



Tail of male surrounded by narrow, poorly developed caudal alae with stalked papillae. A 

 single spicule with accessory piece or two nearly equal spicules. Female sexual pore towards 

 center of body. Viviparous; embryos develop in Crustacea and insect larvae. 



Parasitic in aUmentary canal of fishes and reptiles. 



Single genus known. 



These forms are often cited as Cucidlatms and Dacnitis 

 cleared up the confusion previously existing in the group. 



Camallanus RaiUiet and Henry 1915. 

 Railliet and Henry have recently 



