NEMATODA 



553 



branches. One of these has a tendency to turn forward at first, but ultimately turns 

 posteriorly parallel to the other. Both turn forward again at a short distance from the 

 anus, and the ovaries lie in the prevulvar region. The eggs are small (o-04-o-045 mm. 

 X 0-025-0-03 mm.) and oblong-oval. They have thick shells, apparently without the 

 polar filaments described for the genotype. 



Owing to the absence of a full description of the genotype of Spinitectiis, the sys- 

 tematic position of this genus is somewhat doubtful. If the present species is correctly 

 assigned to Spiuitectus, the detailed examination of it which it has been possible to make 

 leaves little doubt that the genus belongs to the sub-family Thelaziinae, in an appendix 

 to which it was placed by Baylis and Daubney (1926). 



Family CUCULLANIDAE 



Cucullanus fraseri, sp. n. 



(Figs. ID and 11) 



This species occurred in the rectum of Chaenocephalus acerafus (four collections, 

 including types) off South Georgia 

 (Stations 45, 154, MS 68 and Gryt- 

 viken), and of Trematomiis hansom 

 (one collection, off South Georgia, 

 Station 154). 



The male (of which there is only 

 a single specimen) is 5 mm. in length 

 and 0-29 mm. in maximum thickness. 

 Mature females are 6-7 mm. long 

 and about 0-4 mm. thick. The cuti- 

 cular striations are at intervals of 

 about 0-0025 nim. The opening of 

 the mouth is slightly tilted dorsally. 

 The cuticle of the cervical region is 

 relatively very thick. There is a pair 

 of prominent cervical papillae at 

 0-33 mm. in the male, and about 

 0-4 mm. in the female, from the 

 anterior end. The expanded anterior 

 portion of the oesophagus contains 

 paired, latero-ventral thickenings 

 within its muscular walls. At about 

 the level of the cervical papillae the 

 oesophagus becomes very narrow, 

 and at a point a little behind them (o-4-o-45 mm. from the anterior extremity) is 

 surrounded by the nerve-ring. Behind this point the oesophagus increases again in 



Fig. 10. Cucullanus fraseri. Anterior end of female : A, 

 dorsal view; B, lateral view, c, intestinal caecum; 

 c./)., cervical papilla; e., excretory pore; «., nerve-ring. 



