28 ASCAROIDEA 



papillae present. Spicule single. Tail of female very long. 

 Vulva at about posterior third of body. Female genital tubes 

 paired, opposed. Eggs regularly oval, containing embryos 

 when laid and with spiral filaments wound round the shells. 



Hab. Intestine of aquatic Beetles. 



Genotype : P. \Oxyuris] spirotheca (v. Gyory, 1856). 



V. Gyory, 1856, Sitz. k. Akad. Wiss., Wien, xxi, 327 ; 

 Diesing, 1857, Denkschr. k. Akad. Wiss., Wien, xiii, 10; 1861, 

 Sitz. k. Akad. Wiss., Wien, xlii, 614, 637 ; Railliet & Henry, 

 1916, Compt. rend. Soc. Biol., Paris, Ixxix, 114. 



14. Passalurus Dujardin, 1845. 



Lips not apparent. Pharynx contains three denticles. 

 Oesophagus with a prebulbar swelling and a distinct bulb. 

 Tail of male ends in a long spike. Caudal alae extend poste- 

 riorly to the origin of the spike, and are supported at this 

 level by a pair of pedunculate papillae. In addition to these 

 there is a pair of small sessile papillae behind the cloaca, and 

 three pairs of large sessile papillae at the level of the cloaca. 

 A single relatively short spicule. No accessory piece. Tail 

 of female marked externally in its distal portion -with pro- 

 minent annular tliickenings. Vulva anterior, postoesophageal, 

 sometimes on a short vaginal outgrowth. Common trunk 

 of uterus long. Uterine branches parallel. There is in 

 the female a long filament lying freely in the body-cavity, 

 extending from in front of the vulva to the region of the anus. 



Hab. Caecum and large intestine of Hares and Rabbits (one 

 species known). 



Genotype : P. [Oxytiris] ambiguus (Rudolphi, 1819). 



Rudolphi, 1819, Entozoorum Synopsis, 19, 229 ; Dujardin, 

 1845, Histoire nat. des Helminthes, Paris, 230, 231 ; Seurat, 

 1916, Compt. rend. Soc. Biol, Paris, Ixxviii, 67 ; Hall, 1916, 

 Proc. U.S. Nat. Mus., 1, 68. 



15. Weileomia Sambon, 1907. 



Lips large and broad. luterlabia present, directed inwardly. 

 Oesophagus with a prebulbar swelling and a distinct posterior 

 bulb. Cervical alae may be present or absent. Intestine 

 shows at least one anterior and one posterior dilatation, but 

 the characters of these arc not constant. Tail of male slightly 

 alate, with one pair of large postanal papillae, and a pair at 

 the level of the cloaca. A single spicule and an accessory 

 piece present. Behind the postanal papillae the tail diminishes 

 to a slender filament. Tail of female conical and marked 

 externally with a spiral thickening. Vulva in anterior half 

 of body, at the end of a long tubvilar vaginal outgrowth. 



Hab. Alimentary canal of Rodents. 



Genotype : W. mitchelli Sambon, 1907. 



