416 Mr. J. Lycett on Fossil Shells from the 



apex subcentral ; costae about forty-two, large, nearly equal, crossed 

 by numerous encircling lines. 



13*. Rimula minutissima ; almost microscopic, conical; apex 

 curved ; ribs radiating, rounded, numerous, closely arranged, in- 

 dented by encircling striae ; under surface nearly orbicular. 



17. Nerita cassidiformis ; subhemispherical, angulated ; spire dis- 

 coidal ; an elevated smooth encircling carina divides the body-whorl 

 into two portions, the upper of which is flat and has a few fine encir- 

 cling lines ; on the lower portion the lines are larger, roimded and 

 closely arranged. 



43. N. lineata ; very oblique ; spire of several whorls, not elevated 

 and nearly concealed ; surface with numerous very fine longitudinal 

 radiating lines. 



53. Natica Leckhamptonensis ', spire elevated, whorls convex, the 

 last enormously expanded, upper surface of the whorls rounded and 

 sulcated ; aperture very effuse, orbicular. Only casts known. A gi- 

 gantic species. 



23 & 27. Monodonta heliciformis and M. Icevigata ; these shells 

 are smooth and de})ressed ; they have the tooth of Monodonta, but 

 are without any basal sulcus or umbilicus ; they will appear in the 

 Great Oolite monograph under the new generic name Alostoma. 



26. Delphinula quaterno-cingillata ; subglobose ; spire of several 

 whorls, angulated ; longitudinal costse large, elevated, rather angular, 

 impressed by numerous transverse lines ; umbilicus costated ; aperture 

 orbicular. 



25. Littorina nana; small, smooth, thick ; spire elevated; whorls 

 few, convex, narrow ; aperture rather small. 



9. Emarginula alta ; shell much elevated, compressed laterally ; 

 apex curved posteriorly, the convex side beneath the apex having 

 narrow, simple, smooth elevated ribs, of which the middle one is the 

 most prominent ; there are also slight traces of smaller costse upon the 

 flattened sides of the shell ; the height exceeds the length of the aper- 

 ture : rare. 



30. Turbo elaboratus ; ovate ; spire elevated, whorls five, slightly 

 convex and angulated ; surface above the angle smooth, horizontal, 

 or even slightly concave, encircling ribs numerous, elevated, crossing 

 numerous longitudinal elevations or costse, which are indistinct upon 

 the last volution ; aperture oval, its length rather more than half of 

 the entire shell. Axis 1 1 lines : rare. 



33. Turbo Cheltensis ; small ; spire elevated, whorls five, convex, 

 nodulated, nodules in four rows, about sixteen in a volution, the no- 

 dules of each row connected by an encircling line ; nodules large, di- 

 minishing in size upwards in each successive row ; length ^th of an 

 inch. 



34. Turbo varicosus ; turreted, whorls six, convex, each with four 

 encircling, rounded and smooth costse crossing about eight large lon- 

 gitudinal elevations, which pass rather obliquely from left to right. 

 Axis 2 lines. 



37. Trochus bi-cingendus ; elevated, whorls rather concave, with 



