HELIGMOSOMINAE 187 



Subfam. 2. HELIGMOSOMINAE Travassos, 1914. 



Slender forms. Buccal capsule absent or rudimentary. 

 Vulva situated close to anus. Female genital tube single. 



1. Heligmosomum Railliet & Henry, 1909. 



Usually minute forms, not spirally coiled. Cuticle of 

 normal thickness, with prominent transverse striations and 

 longitudinal markings, of which the dorsal and ventral may 

 be very salient. Head with a cuticular dilatation. Bursa 

 of male large, trilobate. Ventral rays widely separated and 

 divergent distall3^ Postero-lateral ray relatively long and 

 divergent from the other lateral rays. Externo-dorsal rays 

 originate high up on the main dorsal trunk, and are short 

 and thin, not reaching the margin of the bursa. Dorsal ray 

 usually fairly thick, bifurcating distally. A pair of accessory 

 branches spring from the bifurcate portion. The terminal 

 branches are bidigitate. Spicules long, filiform. Accessory 

 piece absent or poorly developed. 



Hab. Alimentary tract of Rodents and Marsupials. 

 Genotype : H. [Strongylus] costellatum (Dujardin, 1845). 



Dujardin, 1845, Histoire nat. des Helminthes, Paris, 116; 

 Railliet & Hemy, 1909, Compt. rend. Soc. Biol., Paris, Ixvi, 

 86; Hall, 1916, Proc. U.S. Nat. Mus., 1, 149; Travassos, 

 1921, 3Iem. Inst. Oswaldo Cruz, Rio de Janeiro, xiii, 86. 



2. Heligraosomoides Hall, 1916. 



Body commonly coiled spirally. Cuticle with transverse 

 and longitudinal striations, that of the head slightly inflated. 

 Bursa of male wide, without separate dorsal lobe or mid- 

 dorsal incision. Ventral rays divergent from each other. 

 Externo-dorsal rays long and slender, arising separately from 

 the dorsal ray. Dorsal ray extremely short, with four small 

 branches. Prebursal papillae long and apparently within 

 the bursa. Spicules long and filiform. Accessory piece 

 absent. Tail of female truncate, with a slender terminal 

 spike. Eggs segmenting when deposited. 



Hab. Intestine of Rodents (one species known). 

 Genot3rpe : H. [Strongylus] jyolygynis (Dujardin, 1845). 



Dujardin, 1845, Histoire nat. des Helminthes, Paris, 116; 

 v. Linstow, 1878, Arch. f. Naturg., xliv, 218; Hall, 1916, 

 Proc. U.S. Nat. Mus., 1, 149; Boulenger, 1922, Parasitol, 

 xiv, 206. 



Hall erected the genus Heligmosomoides for the reception 

 of H. linstoioi Hall, 1916 (= *S'. polygi/rus v. Linstow, 1878), 

 believing that *S'. polygyrus v. Linstow was different from 



