NO. 2131. NEMATODE PARASITES OF RODENTS— HALL. 99 



Female 5.28 mm. long and 350 [i thick ; the long finely pointed tail 

 is two-elevenths of the total length of the body. The vagina opens 

 far anterior of the middle of the body and divides the anterior from 

 the posterior portion in the ratio of 19 : 41 ; it extends posteriorly 

 and the ovaries extend to a point near the esophageal bulb. The 

 small eggs are 80 by 23 n. in diameter and are uncommonly numerous. 



Host. — Geosciurus capensis {Xerus setosus). 



Location. — Intestine. 



Locality. — Rehoboth, German Southwest Africa. 



Seurat (1915&), in his paper describing DerTYhatoxys getula, notes 

 in comment on that species that it has very close affinities with 



0. polyoon. As a distinguishing feature he notes the cuticular foi-- 

 mations in the form of a comblike structure in D. getula. It seems 

 quite likely that closer inspection would show the presence of these 

 structures on 0. polyoon., as it has other features, among them the 

 pecidiar distribution of pigment in the esophagus, in common w^ith 

 species of DerTnatoxys. The present w-riter is of the opinion that 

 more study will probably show that this species should be trans- 

 ferred to the genus Dennatoxys. 



Genus DERMATOXYS Schneider, 1866. 



Generic diagnosis. — Oxyurinae (p. 65) : Males with a curving 

 longitudinal row of transverse comblike crests on the ventral surface. 

 Cervical alae present. Esophageal bulb with or without teeth. 

 Males with very long well - developed caudal bursa. Massive 

 deep colored ovaries in the region of the vulva, communicating by 

 narrow oviducts with the uteri ; the two uteri unite in the vicinity of 

 the anus to form the long ovijector which extends anteriorly to the 

 vagina. 



Type-species. — Dermatoxys veligera (Rudolphi, 1819) Schneider, 

 1866. 



ANALYTICAL KEY TO SPECIES OF DEEMATOXYS. 



1. Esophageal bulb without teeth. Male with 10 to 17 crests on the ventral 



surface ; over 10 mm. loug. Female over 15 ram. long. 



Dermatoxys veligera, p. 99. 

 Esophageal bulb provided with teeth. Male with over 20 crests on the ven- 

 tral surface ; less tlian 5 mm. long. Female less than 10 mm. long. 



Dermatoxys getula, p. 103. 



DERMATOXYS VELIGERA (Rudolphi, 1819) Schneider, 1866. 



/Synonym. — Ascaris veligera Rudolphi, 1819. 



Specific diagnosis. — Dermatoxys (p. 99) : Wliite worms, the body 

 rather straight and stiff. Cuticle with fine, transverse striations, 

 spaced at intervals of about 5 jtt in the middle portion of the body and 

 at wider intervals in the posterior portion. Two cervical alae ex- 



