PROSOBRANCHIATA. 239 



both cite Barton as a locality for this well-marked species, I have not been fortunate 

 enough to meet with any specimen of it from that locality ; it is confined, I believe, to 

 the lower beds of the middle eocene formations. It is found plentifully at Bracklesham 

 Bay, of which locality it may be said to be one of the characteristic fossils : it 

 also occurs at Stubbington and White-Cliff Bay, and in the synchronous beds at 

 Bramshaw. 



No. 160. Pleurotoma conica, F. E. Edwards Tab. XXVII, fig. 8. 



P. testa elongatd, fusiformi, omnino concentrice sulcata, unicd serie tuberculatum munitd ; 

 spird conica, elevatd, dimidium totius testa in longitudine superanti •• anfractibus convexius- 

 culis, antice subito coarctatis, suturd conspicud separatis ; marginibus posticis latis, pauxil- 

 lulum declivis, cavatis ; ultimo anfractu in canali longiusculo terminanti ; tuberculis longi- 

 tudinaliter compressis, obliquis, curvis : aperturd oblongo-ovali ; labro arcuato ; sinu lato, 

 sub-trigono, in p) arte anticd marginis collocato. 



Shell elongated, fusiform, concentrically furrowed, and bearing on the shoulders a 

 single row of tubercles : the spire conical, rather thick, and much elevated, exceed- 

 ing one half of the whole shell in length. The whorls are slightly convex at the 

 shoulders, rather suddenly contracted in front, and separated from each other by a 

 very conspicuous suture ; the posterior margins are wide, very slightly depressed, 

 rather deeply channeled along the middle, and a little thickened on the sutural edge. 

 The tubercles, which are somewhat numerous, are longitudinally compressed, narrow, 

 oblique, and curved ; the concentric furrows are nearly regular, shallow, and separated 

 by narrow, rounded ridges, of which, as they approach the beak, every alternate one 

 becomes more prominent than the rest. The aperture is of an oblong-oval form, and 

 terminates in front in a slightly produced, widish canal ; the outer lip is moderately 

 arched ; and the sinus, which is placed in the very front part of the posterior margin, 

 almost on the shoulder of the whorl, is wide and sub-trigonal in shape. 



This species, characterised by its thick, elevated, conical spire, is apparently con- 

 fined to the older eocene beds in the neighbourhood of London. I have not met with 

 any specimen of it either from Clarendon Hill or from the synchronous formations in 

 Hampshire. 



Size. — Axis, 1 l-12ths of an inch ; diameter, 4-12ths of an inch. 



Locality. — Highgate. 



