182 STRONG YLOIDE A 



accessory branches and bidigitate terminations. Prebursal 

 papillae present. Spicules slender, bifid distally, each branch 

 ending in a barb, one branch more or less enfolding the other 

 laterally and ventrally. Accessory piece apparently absent. 

 Eggs segmenting when deposited. 



Hab. Alimentary tract of Rabbit (one species known). 

 Genotype : 0. [Obeliscus] cuniculi (Graybill, 1923). 



Graybill, 1923, ParasitoL, xv, 340; and 1924, xvi, 317. 



7. Hyostrongylus Hall, 1921. 



Cervical papillae present. Bursa with well-developed 

 lateral lobes and a small, distinct dorsal lobe. Latero-ventral 

 ray larger than ventro -ventral ray, its tip turning ventrally 

 towards that ray. Postero-lateral ray rather widely divergent 

 from the remaining lateral rays. Externo-dorsal rays well 

 developed. Dorsal ray fairly long, bifurcate at its tip, and 

 having a pair of small accessory branches at about one-third 

 of its length from the tip. Prebursal papillae present. 

 Spicules with bifid terminations. An accessory piece and a 

 " telamon " present. Eggs segmenting when deposited. 



Hab. Stomach of Suidae. 



Genotype : H. [Strongi/lus] rubidus (Hassall & Stiles, 1892). 



Hassall & Stiles, 1892, Journ. Comp. Med. Vet. Arch., New 

 York, xiii, 207; Hall, 1921, Proc. U.S. Nat. Mus., lix, 543. 



8. Ostertagia Ransom, 1907. 



Cuticle marked with twenty-five to thirty longitudinal ridges. 

 Cuticle of head may be slightly dilated. Cervical papillae 

 present. Mouth-cavity small. Bursa with two lateral lobes 

 and a smaller dorsal lobe. Ventral rays close together, 

 parallel. Dorsal ray with two main branches, each giving off 

 one or two short accessory branches. Attached to the pos- 

 terior end of the male, towards the dorsal side and within the 

 bursa, is an accessory bursal membrane, with a free posterior 

 edge, and supported by two slender, divergent rays. Pre- 

 bursal papillae present. Spicules short, divided distally into 

 two or three terminal processes. An accessory piece may be 

 present or absent. Vulva naked or covered by a flap. 



Hab. Stomach of Ruminants and Opossums. 

 Genotype : 0. [Strongylus] ostertagi (Stiles, 1892). 



Stiles, 1892, Journ. Comp. Med. Vet. Arch., New York, 

 xiii, 147; Ransom, 1907, U.S. Dept. Agric, Bur. Anini. 

 Indust. Circular 110, 2; 1911, U.S. Dept. Agric, Bur. Anim. 

 Indust. Bull. 127, 55; Travassos, 1921, Mem. Inst. Oswaldo 

 Cruz, Rio de Janeiro, xiii, 56. 



