NO. 2012. A NEW NEMATODE FROM THE COYOTE— HALL. 81 



of smaller teeth very likely represented in the male, but not evident 

 in my material. The large tooth seems to be borne on a chitinous 

 projection originating on the dorsal side of the capsule, a condition 

 somewhat similar to that jfigured by Jagerskiold for R. affinis. There 

 is also another tooth evident toward the ventral side of the base of the 

 capsule from the tooth already noted. The head papillae are not well 

 defined, and are not represented in the figure. The anterior end of 

 the first latero-ventral comb is about 55 pt back of the base of the 

 buccal capsule. 



Host. — Canis nehracensis. 



Location. — Small intestine. 

 • Locality. — Amo, Colorado, 18 miles east of Colorado Springs. 



Type-spedmen.— Cat. No. 16218, U.S.N.M. (Bureau of Animal 

 Industry hekninthological collection); collected by M. C. Hall, 

 October 3, 1911. 



The following key is intended only to show the position of R. 

 spleTidida with relation to the other species of the genus, and hence 

 the majority of the species are covered simply as a group. Part of 

 the characteristics of some species are derived from Jagerskiold's 

 figures unsupported by any statement in the text, but his excellent 

 figures seem to warrant this. 



Key for distinguishing Rictularia splendidafrom other species. 



1 . Females with cuticular formations anterior of vulva comb-shaped ; posterior of vulva 



they become spine-shaped, the transition being in the region of the vulva and 

 fairly distinct. Males with latero-ventral combs not extending posteriorly to 

 thecloacal &peTture.. Rictulariaspp. parasitic in bats, insectivores, and rodents. 

 Females in which the transition from combs to spines is very gradual and remote 

 from the vulva. Males with latero-ventral combs extending posteriorly prac- 

 tically to the cloacal aperture Rictularia spp. parasitic in carnivores 2. 



2. Females with 136 to 138 combs and spines; ^^Ilva posterior of esophagus; anterior 



end of first comb its own length, or farther, from the base of the buccal capsule. 

 Males with 8 large midventral fans, almost semicircular in outline, just anterior 

 of cloaca; 108 or 109 latero-ventral combs; 3 pair of large conoidal pre-anal 



papillae, spicules 207 fi long Rktularia splendida. 



Females with fewer combs and spines or with vulva usually anterior of the posterior 

 end of esophagus; the first comb distinctly less than its own length from the 

 base of the buccal capsule. Males with fewer and flatter fans, more or else 

 fewer latero-ventral combs, no large conoidal pre-anal papillae, spicules distinctly 

 shorter or longer ^ 3. 



3. Females with 126 to 135 combs and spines and with vulva always posterior of esopha- 



gus. Males 4.8 mm. long, with 7 midventral fans, 96 latero-ventral combs, 



spicules 170 PL long Rictularia cahirensis. 



Females with 127 to 137 combs and with vulva usually anterior of posterior end of 

 esophagus. Males 7 to 8.5 mm. long, with 6 midventral fans, 111 latero-ven- 

 tral combs, spicules 220 to 230 ft long Rictularia affinis. 



The extent of the latero-ventral combs in the male is hard to judge 

 from descriptions and figures given. It may be that it wUl not serve 

 to separate the males parasitic in carnivores from those in other host 

 groups. 



95278°— Proc.N.M.vol.46— 13 6 



