1922.] 



H. A. Baylis and R. Daubney : Parasitic Nematodes. 



285 



275 mm. in length and 0^14 mm in thickness. The intestinal caecum is broad, and 

 reaches to within 0*69 mm. of the head-end. There is a short ventriculus, measuring 

 about 0*14 mm. in length and about as 

 broad as long. From this is given off a 

 posterior caecum which is 07 mm. in 

 length and 0*15 mm. in thickness. 



The spicules are equal, long and slen- 

 der, measuring i*8 mm. in length and 

 0*022 mm. in breadth. They consist of 

 a cylindrical shaft with narrow lateral 

 alae. The cloaca is situated at 0*125 

 mm. from the tip of the tail (fig. 20), 

 which is abruptly attenuated to a coni- 

 cal point. There are ten pairs of post- 

 anal papillae, of which the first, fourth, fifth and seventh are latero- ventral. The 

 remaining six pairs are lateral and pedunculate, and fall into two groups : a group 



FtG. 19 — Contracaecum engonium. Head of male: 

 dorsal view. 



i., interlabium. 



Fig. 20. — Contracaecum engonium. Tail of male ; ventral view. 



of two pairs (the second and third) close to the tip, and a group of four pairs extend- 

 ing from about the middle of the tail almost to the cloaca. 



Contracaecum schizo thoracis, sp. nov. 

 (Figs. 21, 22.) 



Host: Schizothorax zarudnyi* Position: intestine. Locality: Hamun-i-Hel- 

 mand, Seistan, Eastern Persia. 



This is a relatively short and stout species, tapering to a considerable degree at 

 each end. The male is 1675 mm. long and 08 mm. thick; the female 20*2 mm. and 

 i*o mm. respectively. The cuticular striations are 4~5/x apart. The diameter of 

 the head is 0*2-0-22 mm. The lips (fig. 21) are small, with a deep indentation in the 

 middle oi: the anterior margin, cuticular flanges at the sides, and a projection on the 

 inner surface at each anterior angle. The dorsal lip bears two large, lozenge-shaped 

 papillae, the ventro-lateral lips one each towards the ventral side. The interlabia 



