No. 2386. TWO NEW GENERA OF NEMATODES— HA LL. 543 



strongylidae as Cooperia Ransom, 1907, Ostertagia Ransom, 1907, 

 and Ornithostrongylus Travassos, 1914, but it differs from these 

 genera in certain respects which appear to be of generic value. The 

 generic name Hyostrongylus is therefore proposed for it, with the 

 following diagnosis: 



HYOSTRONGYLUS, new genus. 



Generic diagnosis. — Trichostrongylinae : Male bursa with small but 

 distinct dorsal lobe and well-developed lateral lobes. (There is a 

 distinct bulla just anterior of the bursa in the type species.) The 

 latero-ventral ray is larger than the ventro-ventral ray, and its tip 

 is turned back towards the ventro-ventral. ,^ | i 



The externo-lateral and medio-lateral rays \ ;: j 



diverge slightly, the postero-lateral ray di- 

 verging more widely from the medio-lateral. fifcf-spte. 

 The short externo-dorsal ray arises at the 

 base of the dorsal ray and lies about midway ^^4^f-£ 

 between the postero-lateral rays and the short 

 dorsal ray. The dorsal ray bifurcates near 

 its tip, and has also two small branches at 

 about two-thirds of the distance from the 

 base. Two equal spicules (120 /j. long by 20 n 

 wide anteriorly in the type species) , tapering ^ / 

 to a point, with a wavy ridge running the 

 length of the spicule and supporting a curved 

 membranous portion, which terminates in a 

 second point. Posterior of the position usu- 

 ally occupied by these spicules in the body is 

 a narrow brown gubernaculum (60 ix long in FlG - i— hyostrongylus rubidus. 



, ... I'll 111/- CLOACAL REGION IN MALE SHOW- 



tne type species) , situated m the dorsal wall of ING IEUM0N . highly magni- 

 the cloaca and terminating by a colorless con- FIED - 

 nection in a brown, oblong structure. Ventral of this is a structure 

 (fig. 1), readily seen in fresh material, but so transparent as to be 

 difficult to detect in glycerine jelly mounts or alcoholic material. 

 This structure has a central portion shaped like a spur or a wishbone, 

 situated in the ventral wall of the cloaca near its aperture, and with 

 the point of the spur extending anteriorly; the two posterior points 

 of the spur turn dorsally into the lateral walls of the cloaca and then 

 extend anteriorly as flattened curved plates in the lateral walls of the 

 cloaca. This structure I have named the telamon, a term of Greek 

 origin used in architecture for an ornamental supporting structure. 

 In the female worm the tail is rounded, not mucronate; the anus 

 is very near the posterior end of the body and the vulva is about 

 one-sixth to one-seventh of the body length from the posterior end; 



