GASTEROPODA. 131 



convex, projecting or subangulated at the upper part, and obtusely angular at the base, 

 finely striated transversely ; aperture subquadrate, with a moderately sized umbilicus, 

 which is sometimes entirely closed. 



Axis, nearly \ an inch. 



Locality. Red Crag, Sutton. 



Mam. Crag, Bramerton. Recent, Britain. 



I have met with this shell at one locality only in the Red Crag, where it is not rare. 

 In some specimens the spire is highly elevated, in others it is much depressed, while 

 others, again, preserve an intermediate character. The umbilicus in my specimens is 

 also variable ; in some it is open, while in others it is quite covered, depending upon 

 the elevation or depression of the spire, and also on the extension of the left lip : in the 

 fossil that covering is sometimes broken away, but at other times it is open, where 

 there has been no fracture. 



14. Trochus cinerarius. Linn. Tab. XIV, fig. 7. 



Trochus cixerakius. Syst. Nat. p. 1229. 



— Mont. Test. Brit. p. 284. 



Trochus lineatus. Da Costa. Brit. Conch, t. 3, fig. 66. 



Tr. Testa crassd, orbieulato-convexd, vel obtuso-conicd ; apice obtuso ; anfractibus sub- 

 planulatis, transversiw striatis ; ad basim obtusicarinatis ; aperturd tetragond ; timbilico 

 tecto. 



Shell thick and strong, obtusely or depressedly conical, with an obtuse apex, 

 transversely striated ; volutions rather flat, obtusely carinate at the edge ; base some- 

 what flat ; columella obhque ; aperture subtrapezoidal ; umbilicus closed. 



Axis, \ an inch. 



Locality. Red Crag, Walton Naze and Sutton. Recent, Britain. 



But few specimens of this species are in my cabinet. They appear to resemble 

 the well-known recent species, and it is, in consequence, considered identical ; a few- 

 remains of colour in one specimen, like that upon the recent shell, cross the Unes of 

 growth at nearly right angles, and the umbilicus is quite closed. T. perforatus, 

 Smith (Mem. Wern. Nat. Hist. Soc. vol. viii, fig. 3-4), is probably a variety of this 

 species. 



15. Trochus cineroides. S. Wood. Tab. XIV, fig. 8, a — b. 



Trochus cineroides. S. Wood. Catalogue 1842. 



Tr. Testd crassd, orbictdari, depresso-conicd ; apice obtuso ; anfractibus convexiusculis, 

 transversim striatis ; striis crenulatis ; umbilico magno aperto ; columella obtuse uniplicatd. 



Shell thick and strong, obtusely conical ; volutions slightly convex, transversely 

 striated, with rough crenulated striae ; base of volution obtusely carinate, with a large 

 open umbilicus, and a projection, or obsolete tooth, upon the columella. 



Axis, I of an inch. 



Locality. Red Crag, Walton Naze and Sutton. 



