NO. 2350. NEMATODE GENUS NEMATODIRUS—MAY. 583 



anus 106 [>. from posterior truncated end. Ovijectors very long, 

 unequal, being, respectively, 3.2 and 1.4 mm. long, and both passing 

 backward in body. Eggs, 220 to 280 [jl by 110 to 115 [x. 



Hahitat. — Small intestine of dromedary. 



Distribution. — Africa. 



NEMATODIRUS DROMEDARII. new species. 

 Plate 32, fig. 22 ; plate 35, fig. 31. 



Sjyecific diagnosis. — N eTnatodirus : Species large. Male, 10 to 15 

 mm. long and 200 to 250 \i. in maximum diameter. Bursa resembles 

 that of N. helvetianus. Bosses few, containing granular substance. 

 Striations on bursa present. Spicules, 5 to r),36 mm. long, provided 

 with a sharp terminal piece, as in N. flicoUis. Esophagus, 500 to 

 600 [X long, slightly longer in the female than in the male. Diameter 

 of head, 50 to 55 [i. Female, 20 to 29 mm. long, with vulva one- 

 third of the body length from the anterior end, and anus 145 to 150 ti, 

 from the truncated posterior end. Ovijectors very long, as in A''. 

 viauritanicus. Maximum diameter of female 450 to 500 [x. Eggs 230 

 to 260 [JL by 100 to 120 [x, with smooth shells of nearly uniform thick- 

 ness. 



Hahitat. — Small intestine of dromedary. 



Distrihufion. — France. 



Type specimens. — U.S.N.M, Helminthological Collections, No. 

 19303, collected from a dromedary by A. Railliet in France. (Sepa- 

 rated from No. 2760, JV. spathiger.) 



REMARKS ON MORPHOLOGY. 



In an attempt to find specific differences among members of the 

 genus Nematodirus besides those of the bursa and spicules of the 

 males, various details of morphology were studied in the specimens 

 available. In the case of the short-spiculed forms {N. -fili^ollis., N. 

 spathiger., N. ahnor7nalis, and N. helvetianus) , however, it was im- 

 possible to find characters whereby the females could be distin- 

 guished. 



HEAD AND NECK REGION. 



The cuticula of the portion of the body over the region occupied by 

 the anterior one-third of the esophagus is frequently inflated (plate 

 29, figs. 1, 2). This inflation is variable within the same species, but 

 seems to occur in all of them. The inflated portion of the cuticula 

 is marked by superficial coarse rings, and, in stained specimens, by 

 deeper, stainable rings. The mouth is an oval terminal opening in 

 the cuticula covering the head, leading into a very short buccal 

 cavity, usually not more than 5 [x in length. Surrounding the mouth 

 opening are six circumoral papillae. The two lateral papillae are 

 comparatively large and are easily visible in toto mounts. The ven- 

 tral and dorsal pairs are much smaller and are visible in toto prepara- 



