147 



whorl much depressed above, at, and behind the aperture. Aperture, 

 rather oblique in incomplete shells, subelliptical and subangular 

 above, like a hanging pear — in finished shells, subcircular, rather 

 dilated below on the right side, and the angularity above becoming 

 almost obsolete by the thickening of the outside. Peritreme, well 

 thickened and blunt all round. Umbilicus, deep and comparatively nar- 

 row ; greatest breadth, that is from side to side at the umbilical keel*, 

 about 0'36, and least breadth 0*28. Umbilical keel, narrowly and 

 roundly pinched up, the striae of growth extending over it imbricatedly 

 from the hollow. Operculum, greatest breadth 0*5 1, least breadth0*46 

 — slightly concave externally, with about f 9 outward bending, 

 spiral whorls of laminae rising from its plane, the summits of which 

 spread, and are reflected outwards, but widely separated from one 

 another, nearly parallel to the plane, and striated eccentrically, as like 

 water flying off a turned wheel by centrifugal force ; lamina well 

 detached above from the plane, and from each other whorl. Height 

 of shell, 1 inch; greatest breadth 1*2, least breadth 1 inch J. 



C. corrugatus, var. a (?), Chitty. 



This shell differs from C. corrugatus in being much smaller. 

 HeightO'8, greatest breadth 0"94, least breadth0*75 ; greatest breadth 

 of umbilicus 0'27, least breadth 0*2 ; greatest breadth of operculum 

 0*43, least breadth 0*37. The corrugation is finer. It is sometimes 

 quasi smooth below, and marked with bands like C. Jamaicensis with 

 transverse raised sub-obsolete lines. Umbilical keel is less promi- 

 nent. 



Whorls 5. Whorls of operculum about 6 or 7. 



C. Portlandensis, Chitty. Portland. 



Form, depressed- turbinate. Colour, blueish-white with a deep bistre 

 brown epidermis ; apex blood-red sometimes. Sculpture, 3\ of 

 upper whorls coarse, striae of growth becoming thenceforth deeply 

 corrugated vertically on the upper part of the last whorl until about 

 the last third, where the corrugation ceases ; the striae of growth are 

 finer and a few pits occur, and a few transverse obsolete ridges 

 appear. No corrugation at the periphery : a few pits, and a slight 

 corrugation surround the outside of the umbilical keel. Umbilical 

 keel and striae of growth within the umbilicus are much stronger 

 than in C. corrugatus. Spire, and outlines like C. corrugatus. 

 Whorls, 5i, last whorl and about ith of penult whorl depressed 

 above, below the suture. Aperture, like C. corrugatus, but rather 

 more expanded on right than on left side ; oblique to axis, as C. cor- 

 rugatus. Peritreme, like C. corrugatus. Umbilicus, much wider in 



* The measurement of the umbilicus in all instances is taken from side to side 

 from the inner edge of the umbilical keel, taking care that the points of the com- 

 passes shall he at a right angle with the axis of the shell. 



t The nuclear centre and second whorl are prohably never seen in mature shells, 

 from their extreme delicacy while young, which causes the appearance of being 

 devoid of laminae in the extreme centre. 



% All my measurements are in decimals of an inch. 



