NEMATODE PARASITES OF RODENTS— HALL. 



173 



RICTULARIA COLORADENSIS Hall, 1916, new species. 



Specific diagnosis. — Rictidaria (p. 1G8) : 



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

 ventral head diameter at the base of the buccal capsule about 70 /x. 



Esophagus 875 fx long. Nerve 

 ring 100 jx from the anterior 

 end of the body. The cuticle 

 is transA'ersely striate, forming 

 annuli 7 to IG /x 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 /x, distinctly less 

 than its own length, posterior 

 of the base of the buccal cap- 

 side. The maximum size is at- 

 tained by the posterior combs 

 wdiich are about 75 /x long and 

 18 II high. There are no mid- 

 ventral fans in the posterior re- 

 gion, such as are observed in 

 species of Rictidaria from car- 

 nivores. There is no bursa. 

 The cloacal aperture is sit- 



TlG. 221— RiCTULARIA COLORADENSIS. MALE 



uated on an elevation and 

 is 165 /x 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 

 aperture. 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 



Fig. 225.— Rictulaeia colokadensis. Posteriob 

 extremity of male. enlarged. 



