NO. 2131. NEMATODE PARASITES OF RODENTS— HALL. 47 



cult to see more th:ni two pairs of papillae on one or both sides of 

 the tail membrane, possibly due to doubling or crumpling. In addi- 

 tion to the six pairs of papillae which sustain the bursa, there are 

 four other pairs. Of these, two stalked pairs are in the region of 

 the sucker, the apparent relation to the sucker being rather variable. 

 The other two pairs are sessile and are in the vicinity of the cloacal 

 aperture ; they are rather difficult to observe accurately. The cloacal 

 aperture is variable in shape or presents variations due to point of 

 view or distortion. The sucker (fig. 53) is a powerful pedunculate 

 structure, with a strong chitinous invest- 

 ment interrupted on the posterior border .^S^Pli^ft^v 

 by a papilliform elevation. The sucker is # '.'^'^. 

 elliptical, with a transverse diameter of 

 about 86 [J, and a longitudinal diameter of 

 65 to 82 [A. There are well-developed mus- 

 cular strands from the base of the sucker 

 to the opposite body wall. The spicules 

 are subequal, 200 to (?) 400 [x in length, 



flattened, and have a pronounced longi- j— — 1 



tudinal striation. They are thickest at the i/iomm. 



proximal end and taper gradually to a fig.ss.-heterakisspumosa. 



. rn, ,, '^. , ", Caudal sucker of male; ven- 



point. ihey are very liexible, and com- teal view. 



monly show^ signs of curving, twisting, and 



bending in mounting. The proximal end terminates in a short open 



hook bending laterally. The distance from the posterior margin of 



the sucker to the tip of the tail is 435 to 500 \k ; the distance from the 



cloacal aperture to the tip of the tail is 250 to 300 y.. 



Female 7 to 13 mm. long with a diameter of 300 to 520 fi. The 

 anus is from 680 to 740 fi from the posterior end of the body. The 

 vulva (fig. 54) is slightly posterior of the middle of the body. It 

 has two prominent transverse lips with one or two cuticular promi- 

 nences before and behind it in the mid ventral line. Each lip of the 

 vulva bears two papillae. The vagina appears to be surrounded by 

 a spiral band for some distance back from the region near the vulva. 

 From the vulva the vagina turns forward for a short distance and 

 then turns and extends posteriorly for a short distance. Apparently 

 it then forks to form the anterior and posterior uterine branches. 

 These extend forward and backward, respectively, and then turn 

 back, transform into the ovaries, and as such make their way in 

 numerous transverse loops through the anterior and posterior ends of 

 the body. The egg has a mamillated shell about 4 n thick and is 55 

 to 60 by 40 to 55 [x in diameter. Eggs segmenting when oviposited. 



Hosts. — Epimys norvegicus {Mus decumanus), Epimys rattus 

 {Mus rattus)., Cricetomys gambianus. 



