145 

 panded in both directions but mostly on the exterior, and is then cun'ed down- 

 wards, presenting a broad rounded summit. A transverse section of the lamina 

 somewhat resembles the italic letter T. 



Mean divergence about 120° ; height .46 inch ; greatest breadth .84 inch ; 

 least breadth .65 inch. 



No. 7. This differs from No. 6: the depression of the last whorl above is rather 

 deeper, and. extends along the penult whorl where it is linear ; the wrinkles are 

 less regular, and are often wanting at the end and lower side of the penult whorl ; 

 the umbilical keel is very strongly developed ; the epidermis is very dark brown ; 

 in the whorls of the opercular lamina, the lateral expansions come in contact, form- 

 ing a covered way beneath. This type inhabits the parish of Portland. It attains 

 a great size and solidity. 



Mean divergence about 120° ; height .85 inch ; greatest breadth 1.36 inch ; 

 least breadth 1.05 inch. 



No. 8 differs from the preceding, in having the whole surface destitute of wrin- 

 kles. 



No. 9 is also like No. 7 ; but its operculum is flatter, and has two more whorls, 

 and all its whorls are therefore narrower ; the epidermis is light brown ; and the 

 wrinkles are nearly obsolete, except a few which are small and well defined near 

 the commencement of the penult whorl. 



Mean divergence 130°; height .6 inch; greatest breadth 1.03 inch; least 

 breadth .81 inch. 



No. 10. The wrinkles are well developed, rather sharp, oblique and regular on 

 the penult and antepenult whorls, and arc nearly obsolete on the last whorl, the 

 lower side of which is quite smooth ; the unibilieal keel is very prominent ; the 

 operculum is like that of No. 9. Some have a few raised spiral lines on the last 

 whorl. 



Mean divergence 125° ; height .55 inch ; greatest breadth .95 inch ; least 

 breadth .75 inch. 



No. 11. White, often reddish ; the epidermis is dark brown, with a while stripe 

 next below the suture on the last whorl : with the transverse striae excessively mi- 

 nute : the wrinkles are very small on the antepenult and penult whorls, and nearly 

 obsolete on the upper part of the last whorl, which is smooth below ; there are a 

 few indistinct spiral striaj ; the umbilical keel is well developed : spire well eleva- 

 ted : whorls nearly five, slightly depressed above ; with a well impressed suture 

 aperture suborbicular. quite pointed and effuse above ; lip well thickened, much 

 advanced on the right side : umbilicus half as wide as the aperture. Operculum 

 like that of No. 9. 



Inhabits St. John's. 



Mean divergence about 130° ; height .55 inch ; greatest breadth .92 inchi 

 least breadth .74 inch. 



No. 12 differs from No. 11 in having the whorls more flattened above, and the 

 aperture more dilated. Operculum as in No. 9. 

 Inhabits the north side, in St. Mary's. 



