NO. 2131. 



NEMATODE PARASITES OF RODENTS— HALL. 



113 



two terminal dorsal rays, each of which terminates in a bifurcation 

 (fig. 140). The externo-dorsal rays originate about halfway between 

 the base of the common trunk and the branching of 

 the main dorsal trunk to form the terminal dorsal 

 rays. The medio-lateral and postero-lateral rays ex- 

 tend almost side by side to the edge of the bursa 

 (fig. 111). The externo-lateral ray terminates about 

 one-third of the distance from the medio-lateral ray 

 to the ventral rays. Vulva in the middle of the body. 

 Type-species. — Ache'dostojna shnpsonl Leiper, 1911. 



ACHEILOSTOMA SIMPSONI Leiper, 1911. 



Specific diagnosis. — Acheilostoma (p. 112) : Cuticle 

 with deep transverse striations in the anterior end of 

 the body. Two large, stout, thorn-shaped cervical 

 papillae curving backward (fig. 138). 



Male 17 mm. long. (See figs. 140 and 141.) 



Female 23 mm. long. Cervical papillae 800 jx from 

 the anterior end. . Collar of oral aperture 4 j;. thick. 

 Esophagus 950 [jl long. Eggs in utero are 55 by 32 ti 

 in diameter " and usually contain a few segments." 



Host. — "A large rodent." 



Location. — " Alimentary canal." 



Locality. — Nigeria, Africa. 



In the absence of any definite statement I have re- 

 ferred Leiper's measurements to the female. His statement that the 

 externo-lateral ray "has a thickness almost equal to the two central 



Fig. 138. —Achei- 

 lostoma SIMP- 

 SONI. Ante- 

 rior EXTREM- 

 I T Y . E N- 



LARGED. Af- 

 ter Leiper, 

 1911. 



Fig. 139.— Acheilostoma simpsoni. Ba.'^e of buccal capsule. Enlarged. 

 After Leiper, 1911. 



rays combined " leaves considerable doubt as to what is meant by the 

 two central rays. If it refers to the medio-lateral and postero-lateral 

 lOGOC—Proc.N.M.voLGO— IG— 8 



