OXYURINAE 29 



Sambon, 1907, Abstr. Proc. Zool. Soc, London, March 26, 15 ; 

 1907, Proc. Zool. Soc, London, 282 ; Hall, 1916, Proc. U.S. Nat. 

 Mtis., 1, 70; Baylis, 1922, Ann. Mag. Nat. Hist., (9) ix, 494. 



16. Syphacia Seurat, 1916. 



Lips distinct. Buccal capsule absent. Oesophagus with 

 a short pharynx, a prebulbar swelling and a distinct posterior 

 bulb. Tail of male ends in a long spike. Caudal alae termi- 

 nate posteriorly at the origin of the tail-spike. Two pairs 

 of sessile preanal papUlae present, one of which is situated 

 on the lip of the cloaca. The caudal alae are supported 

 behind by a pair of large pedunculate postanal papillae, and 

 contain a smaller pair at about the middle. A single relatively 

 long spicule and an accessory piece present. Vulva in anterior 

 region, but postoesophageal. Common trunk of uterus 

 relatively long. Uterine branches parallel, not extending 

 posteriorly as far as the anus. 



Hab. Caecum and large intestine of Rodents. 

 Genotype : S. [Ascaris] obvelata (Rudolphi, 1802.) 



Rudolphi, 1802, Arch. f. Zool. u. Zoot., Brunswick, ii, 18; 

 Seurat, 1916, Compt. rend. Soc. Biol., Paris, Ixxviii, 64; Hall, 

 1916, Proc. U.S. Nat. Mus., 1, 81. 



17. Haplacis RaiUiet & Henry, 1916. 



Head rounded, with three lips and one pair of papillae. 

 Oesophagus proper short and stout, somewhat hourglass- 

 shaped, followed by a distinct spherical bulb. Tail of male 

 tapering, apparently without alae. Three pairs of preanal 

 papillae present. A single large, stout, pointed spicule present. 

 Accessory piece absent. Tail of female tapering. Vulva 

 towards the middle of the body, or somewhat behind it. 

 Vagina very short. Uterine branches opposed. Eggs large, 

 oval, segmenting when laid. 



Hab. Intestine of Myriopoda. 



Genotype : H. [Isacis^ silvestrii (Parona, 1896). 



Parona, 1896, Atti Soc. Ligust. Sci. Nat., Genova, vii. 111 ; 

 RaiUiet & Henry, 1916, Compt. rend. Soc. Biol., Paris, Ixxix, 

 114. 



Beyond the fact that this genus is placed by RaiUiet & 

 Henry among forms with a single spicule and without an 

 accessory piece, and in which the vulva is situated towards the 

 middle or in the posterior half of the body, no characterization 

 of it exists. Wc are unable to extract from the specific 

 description of the genotype any weU-marked characters 

 differentiating it from other Oxyurinae. 



