GASTEROPODA. 125 



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

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

 Tr. conuloides, Lamarck. Trochus laviyatm. 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 stri«, 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 — b. 



Trochus conulus. Linn. Gmel. p. 3579. 



— Lam. 2d edit. Hist. Nat. des An. sans Vert. t. 9, p. 142, 1835. 



— Phil. var. a. En. Moll. Sic. vol. i. p. 1/5, 1836. 



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



— S. Wood. Catalogue 1842. 



Tr. Testa conicd, nitidd, lavigatd; apice acuto, granulato ; mfractibus planis, ad basim 

 angulatis; inferne cingido, crassiusculo marginatis, inflmd facie planatd ; aperturd tetragond. 



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 mto my possession, which appear 

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

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



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. xix, p. 96, pi. 9, fig. 1. 

 — aUADEiciNCTUs. S, IFood. Catalogue 1842. 



Tr. Testd conicd, imperforatd, granulatd; anfractibtis quitique, planiusculis ; cingulis 

 quatuor, elevatis instructis ; ultimo anfractu ad basim mbangulato ; aperturd tetragond. 



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

 ornamented with about four elevated and granulated ridges ; base rather flat ; edo-e of 

 volution subangulated, with a subquadrate or trapezifonn 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 with his recent British species. As the name given in my Catalogue was 



