GASTEROPODA. 125 



Specimens from the Red Crag appear to be very rare ; fig. 9 h is one that approaches 

 nearer our common form; fig. 9/,^ is from the CoralHne Crag, and appears to resemble 

 Tr. comdoides, Lamarck. Trochm laviyatus. Sow., is probably only a specimen of this 

 species, similar to fig. 9 c, which I imagine is an abraded individual from the Red 

 Crag, upon which there is not the slightest vestige of striae, the outer coating having 

 been entirely removed ; its only markings are the lines of growth ; fig. 4 is also pre- 

 sumed to be a monstrous and decorticated specimen of this species. 



3. Trochus conulus. Linn. Tab. XIII, fig. 5, a — h. 



Tkochus conulus. Linn. Gmel. p. 35/9. 



— Lcm. 2(1 edit. Hist. Nat. des An. sans Vert. t. 9, p. 142, 1835. 



— Fh'd. var. a. En. Moll. Sic. vol. i. p. 175, 1836. 



— Thorpe. Brit. Mar. Conch, p. 255, 1844. 



— S. Wood. Catalogue 1842. 



Tr. Testa conicd, nitidd, laevigata; ajpice acuto, granulato ; anfradibus planis, ad basim 

 angulatis; infeme cingulo, crassiusculo marginatis, infimd facie ])lanatd ; aperturd tetragonu. 



Shell conical, smooth, and naked, with an acute and granulated apex ; sides flat, 

 and a distinct ridge at the carinated edge of the volution ; base nearly flat ; columella 

 suboblique ; aperture trapeziform. 



Altitude, 1 inch ; diameter, I. 



Locality. Cor. Crag, Ramsholt. Recent, Mediterranean and Britain. 



But two or three specimens of this species have come into my possession, which appear 

 to correspond with the smooth glossy form of what has hitherto been called T. conulm. 

 It is very possible this may be a variety of T. zizijjJdnus. 



Prof. Forbes and Mr. Hanley are of opinion that T. conulus is specifically distinct from 

 T. zizipliinus, and as those gentlemen are better acquainted with the recent species than 

 myself, I have given it upon their authority. 



4. Trochus formosus. Forbes. Tab. XIII, fiff. 2, a — b. 



Trochus formosus. Forbes. An. and Mag. Nat. Hist. 1847, vol. six, p. 96, pi. 9, fig. 1. 

 — QUADRiciNCTUS. 5. JVood. Catalogue 1842. 



Tr. Testd conicd, imperforatd, granulatd ; anfractibus quinrpie, planiusculis ; cingulis 

 quatuor, elevatis instrudis ; ultimo anfractu ad basi7/i subangulato ; aperturd tetragond. 



Shell regularly conical, with flat sides, and slightly elevated spire ; volutions five, 

 ornamented with about four elevated and granulated ridges : base rather flat ; edge of 

 volution subangulated, with a subquadrate or trapeziform aperture. 



Axis, \ an inch. 



Locality. Cor. Crag, Sutton. 



Red Crag, Sutton. Recent, British Seas. 



I have but a few specimens of this from either formation, and Prof. Forbes considers 

 them identical ^\-ith his recent British species. As the name given in my Catalogue was 



