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 

 hip : 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. 



Tkochus cinerarius. Syst. Nat. p. 1229. 



— Mont. Test. Brit. p. 284. 



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



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

 planulatis, transversim striatis; ad basim obtusicarinatis ; aperturd tetragona ; umbilico 

 tec to. 



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

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

 somewhat flat ; columella oblique ; 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 

 lines of growth at nearly right angles, and the umbilicus is quite closed. T. perfo- 

 rates, 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, fisr. 8, a — b. 



Trochus cineroides. S. Wood. Catalogue 1842. 



Tr. Testa crassd, orbiculari, deprcsso-conicd ; apice obtuso ; anfractibus convexiusculis, 

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



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

 striated, with rough crenulated stria? ; base of volution obtusely carinate, with a 

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



Axis, f of an inch. 



Locality. Red Crag, "Walton Naze and Sutton. 



