116 EEV. R. BOOG WATSON" ON THE 



more crowded. In the interstices a feebler riblet is occasionally 

 intercalated. They die out on the base with a strong, posteriorly 

 convex curve. Spirals — near but not just at the suture the top 

 of each whorl projects in a sharp minute carina, defined by a spiral 

 thread, which forms a small knot in crossing each riblet; about 

 one third down the whorl a very fine sharp thread runs round the 

 shell, rising over, but scarcely forming knots on the riblets. 

 Another one third down a very faint thread appears. The margin 

 of the base is defined by a sharp, minute, knotted, carinal thread, 

 the edge of which may just be traced at the bottom of each whorl, 

 just above the suture, all the way up the spire. The base is plain 

 but for a very faint submarginal thread. The apex is smooth 

 and glossy, with nothing but microscopic evanescent superficial 

 spirals. Over the whole surface of the shell there is a micro- 

 scopic reticulation of faint, pretty equal, longitudinal and spiral 

 scratches. Colour ivory-white. Spire high, narrow, with per- 

 fectly straight conical outlines. Apex truncate, and then finished 

 with a slightly depressed mammillate, glossy, pure white tip, con- 

 sisting of a whorl and a half, which is straight on the top and not 

 oblique. Whorls 9, straight or just faintly concave on the side, 

 slightly scalar as they rise out of one another. The base is not 

 in the least contracted, and is barely convex. Suture only re- 

 cognizable from the slight shoulder of the whorl below it. Mouth 

 small, angularly oval, with a blunt and laterally directed point 

 above, and an oblique canal in front, which, relatively to the size 

 of the mouth itself, is very large. Outer lip very straight, being 

 neither incurved nor patulous, except round the edge of the 

 canal, where it is slightly so. Pillar very short and conical, with 

 an abrupt little, broad, parallel-sided style, with a very oblique, 

 fine, rounded edge, and ending in a fine point on the left. Inner 

 lip a fine glaze on the body and edge of the pillar. H. - 19. 

 B. 0-06. Penultimate whorl, height O028. Mouth, length 

 0039, breadth 0-028. 



This is a peculiarly beautiful shell, and, like C. mcmillanum 

 from the same locality, departing widely in sculpture from the 

 coarse type common to the genus. From that species it differs 

 markedly in its being much stumpier in form and in the carina 

 being placed at the top and not at the bottom of the whorls. 

 From G. amblyterum, another deep-sea form, and which it also re- 

 sembles slightly, it differs in being stumpier and in having a much 

 blunter and shorter apex. 



