150 



at about one half of the last whorl, where the corrugation be- 

 comes coarse, irregular, and ill-defined, till little more than 

 coarse striae of growth are seen behind the aperture. From the 

 periphery downwards, the corrugations on the last whorl, for about 

 its first half, are much closer together than those above, and lie 

 almost horizontally, but inclining from left above to right below ; 

 and, outside the umbilical keel, the rest of the whorl below the peri- 

 phery is much pitted. Striee of growth inside the umbilicus rather 

 fine. Spire much depressed, with convex outlines. Whorls nearly 

 5, well rounded with a deep suture. Aperture well rounded, slightly 

 subangular above. Peritreme rather reflected, and spread on the 

 right, sometimes double above ; thickened (as is usual) on the left, 

 and slightly detached from body- whorl. Umbilicus broad ; greatest 

 breadth, 0'3o ; least breadth, 0*31. Umbilical keel well developed. 

 Operculum moderately concave above, planulate below, rather in- 

 clined to that of C. corrugatus form, from the cross lines on the 

 margin of the spiral lamina being less developed, but otherwise like 

 the C. varians type in general character of closeness to one another. 

 8 or 9 whorls, and still a vacuity in the centre. Height 0*7, greatest 

 breadth 0'98, least breadth, 0-84. 



Var. minor, Chitty, is much smaller ; being, height 0*53, greatest 

 breadth 0*8, least breadth 0*65. 



Var. magna, Chitty, is much more conical j height 0*8, greatest 

 breadth 0-92, least breadth 0'81. 



C. gemma, Chitty. New Hope. 



Form, very much depressed-turbinate. Colour, bluish-white, with 

 a light brown epidermis. Sculpture, like to C. corrugatior, but 

 corrugation commences almost at the first quarter of the 3rd 

 whorl ; corrugation very marked in proportion to size, as in 

 C. corrugatior ; sometimes in zigzag vertically, sometimes with dia- 

 gonal arrow-head-shaped indentations, the points being on the peri- 

 phery, on the last whorl. Spire, much depressed, with convex 

 outlines. Whorls, A\, well rounded with a deep suture, last whorl 

 much depressed. Aperture, widely expanded, especially on the 

 right side and below, slightly angular above. Peritreme, well ex- 

 panded on right side, more separated from body-whorl on left than 

 in C. corrugatior. Umbilicus, broad; greatest breadth, 021, least 

 breadth, 0*16. Umbilical keel, almost obsolete. Operculum, same 

 as in C. corrugatior, with about 9 whorls. Height 0"41, greatest 

 breadth # 66, least breadth 0*51. 



C. zigzag, Chitty. Trelawny. 



Form, depressed-turbinate. Colour, white, with light brown epider- 

 mis. Sculpture, like C. corrugatior in the upper whorls, only 

 very much finer and closer, and more regularly corrugated, in 

 zigzag form, on the last whorl, and finely corrugated all over 

 the under side, except behind the aperture, round the um- 

 bilicus. Spire, moderately elevated, with convex outlines. Whorls, 





