BY N. A. COBB. 153 



the remark that other species if carefully examined would perhaps 

 prove to be also striated. Since making those observations I have 

 continued the impression under which they were written, by the 

 discovery of stria? in a number of other species of Dorylaimus. 

 These stride are generally most clearly visible near the posterior 

 extremity of the animal. The occurrence of spiral markings on 

 the head of Onyx, and of fine transverse stria? in its cuticula, 

 coupled with the general resemblance to Dorylaimus, when taken 

 in conjunction with the observation of fiue stria? on many species 

 of the latter genus and obscure spiral markings on two species, 

 obviously give a new character to the group of Nematodes of 

 which Onyx and Dorylaimus are representatives, and suggest new 

 phylogenetic probabilities. 



The worms belonging to the genus Onyx are readily recognised 

 by the cylindrical neck and peculiar head. The single species 

 now first described is called on account of the perfection of its 

 development 



Onyx perfectus, n.sp. 27 T >\ ^'l '^ °H r94 mm - The cuticula is 

 traversed by twenty-seven thousand transverse stria? and bears 

 throughout the length of the body very slender and rather long hairs 

 These latter are, as usual, longer and more numerous near the head, 

 where their length is about half as great as that of the diameter 

 of the body. When the mouth is closed the anterior extremity is 

 hemispherically rounded. The conspicuous lateral markings are 

 so curved that the right hand one appears as a left-handed spiral 

 passing through about 450° of angular space, and the left hand 

 one as a corresponding right-handed spiral When the worm is 

 placed in profile the spirals appear to be one-half as wide as the 

 pharyngeal bulb, the latter being itself one-half as wide as the 

 head. There are no eyes. When the mouth is closed the 

 summits of the twelve pointed papillae with which the lips are 

 armed may be seen crowded together at the small orifice. When 

 the mouth-parts are thrust forward, the points of the papilla? 

 become separated from each other and then sometimes have the 

 appearance commonly presented by the lips and papilla? of 



