NO. 2131. NEMATODE PARASITES OF RODENTS— HALL. 



173 



RICTULARIA COLORADENSIS Hall, 1916, new species. 



iflc diagnosis. — RiGtular'm (p. IGS) : 

 3 mm. long with a maximum thickness of 250 ^x. Dorso- 

 head diameter at the base of the buccal capsule about TO /^. 



Esophagus 875 /x long. Nerve 

 ring 100 p. from the anterior 

 end of the body. The cuticle 

 is trans\ersely striate, forming 

 annuli 7 to IG y. wide. Stria- 

 tions are not visible posterior 

 of the cloacal aperture. There 

 are 12 pairs of combs (fig. 221), 

 extending from the head almost 

 to the cloacal aperture, the line 

 of combs being continued pos- 

 teriorly by a low cuticular 

 ridge. The first comb ante- 

 riorly is 16 /i, distinctly less 

 than its own length, posterior 

 of the base of the buccal cap- 

 sule. The maximum size^is at- 

 tained by the posterior combs 

 vrhich are about 75 ix long and 

 48 p. high. There are no mid- 

 ventral fans ui the posterior re- 

 gion, such as are observed in 

 species of Rictularia from car- 

 nivores. There is no bursa. 

 The cloacal aperture is sit- 



riG. 224.— RiCTULAELV COLORADENSIS. MALE. 



uated on an elevation and 

 is 165 II from the tip of 

 the blunt, conical tail (fig. 

 225). There is a papilla 

 in the median line on the 

 anterior slope of the ele- 

 vation bearing the cloacal 

 a p e r t u r e. Immediately 

 anterior of this is a pair 

 of papillae. Another papilla is in the median line on the pos- 

 terior slope of the elevation bearing the cloacal aperture. An- 

 other pair is just posterior of this. Two more pairs are located 



xc 



X 



^i"^ 



Fig. 225.— Rictularia colohadensis. Po.steriob 



EXTREMITY OF male. ENLARGED. 



