TRICHOSTRONGYLINAE 181 



dorsal rays long and prominent, arising high up on the median 

 dorsal stem and reaching margin of bursa. Dorsal ray rela- 

 tively long, bifurcate at its tip, each branch again bifurcate. 

 Prebursal papillae present. Spicules long, slender, and 

 branched at their tips to form multiple terminations. An 

 accessory piece present. Vulva sometimes covered by a 

 cuticular process. The body narrows abruptly behind the 

 vulva. 



Hab. Alimentary tract of Rodents. 



Genotjrpe : O. [Strongyhis] strigosum (Dujardin, 1845). 



Dujardin, 1845, Hist. nat. des Helminthes, Paris, 120 ; 

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

 86; Hall, 1916, Proc. U.S. Nat. Mus., 1, 123, 139; Travassos, 

 1921, Mem. Inst. Oswaldo Cruz, Rio de Janeiro, xiii, 70; 

 Cameron, 1923, Journ. Helminthol., i, 71. 



5. Graphidioides Cameron, 1923. 



Cuticle with prominent longitudinal striations. Cervical 

 papillae absent. Bursa v.ith large lateral lobes, joined by 

 a small, ill-defined dorsal lobe. Latero-ventral ray much 

 longer and thicker than, and widely divergent from, ventro- 

 ventral ray. Externo-dorsal rays originate high up on the 

 median dorsal stem, but do not reach the margin of the bursa. 

 Dorsal ray long and slender, cleft near its tip, each branch 

 ending in three short digitations. Prebursal papillae present. 

 Spicules long and filiform, each consisting of two chitinized 

 rods joined at the distal extremity, which is simple. Each 

 spicule possesses a median membranous expansion, and the 

 membranes join each other near the tips of the spicules. An 

 accessory piece present. 



Hab. Stomach of Rodents. 



Genotype : G. [Strongyhis] affinis (Megnin, 1895). 



Mcgnin, 1895, Bull. Soc. Zool. France, xx, 173 ; Travassos, 

 1921, 3Iem. Inst. Oswaldo Cruz, Rio de Janeiro, xiii, 71 ; 

 Cameron, 1923, Journ. Helminthol., i, 71. 



6. Obeliscoides GraybiU, 1924. 



Syn. Obeliscus GraybiU, 1923, nee Humphreys, 1797. 



Cuticle with a number of longitudinal striations. Cervical 

 papillae present. Bursa with large lateral lobes and a small, 

 but well-defined, dorsal lobe. Ventral rays, after a pro- 

 nounced divergence, terminate near each other. The ventro- 

 ventral ray is small, while the latero-ventral is the thickest 

 and longest of all the rays. Antero-lateral ray long and stout, 

 the remaining lateral rays and the externo-dorsal slender and 

 considerably shorter. Dorsal ray short, with a pair of short 



