GASTEROPODA. 71 



C. Testa minima, ci/lindraceo-turritd ; anfractibus planiusculis ; cingulos tres granosos 

 ferentihm ; basi lavi, canali brevissimo. 



Shell small, subcylindrical, and turriculate ; volutions flattish, covered with three 

 transverse granular ridges ; base naked and smooth, with very short canal. 



Axis, \ of an inch. 



Localify. Cor. Crag, Sutton. Recent, British Seas. 



An abundant shell, and very variable in its proportional dimensions : some are 

 tapering and elongate, exceeding in length its diameter at least four times ; while others 

 are nearly half as broad as they are long. It is distinguished by having three sharp 

 ridges of tubercles, and a fourth ridge, which is smaller, without the tubercles, at the 

 base, or rather edge, of the last volution. A canal is formed at the suture by the 

 elevation of the tubercular ridges. The base is generally naked, smooth, and flat ; but 

 in some there is a thick and elevated spiral ridge, behind which is a deep sulcus. 

 Cer. jji/gmceum, Phil., looks like one of its varieties, and the Belgian shell I imagine, 

 from the figure, to be the same. I have fragments which indicate a length of at least 

 three eighths of an inch. 



5. Cerithium metaxa (?). Delle Chiaje. Tab. VIII, fig. 6, 6 a. 



MuEEX METAXA. Bel. CM. Mem. 1826, p. 211, t. 49, fig. 29-31. 

 Cerithium ceepekum. S. Wood. Catalogue 1842. 



C. Testa minima, cylindraceo-turritd ; anfractibus convexis, numerosis; cingulos granu- 

 losos quatuor ferentibus ; basi Icevi ; labro acuto ; canali brevissimo. 



Shell minute, turriculate, and subcylindrical ; whorls numerous, convex, ornamented 

 with four transverse granulated ridges ; base smooth ; outer lip sharp, with very short 

 or emarginate canal. 



Axis, I of an inch. 



Locality. Cor. Crag, Sutton. 



This is not a very abundant shell, and the specimens are generally broken. It 

 appears, however, to differ specifically from C. tuberculare in always having four ridges 

 of granules upon the spire, with a smaller one around the base ; the form of the volu- 

 tion is convex, with the lower portion projecting a little, which gives it a subconoidal 

 form. It appears to correspond with the description given by Delia Chiaje, but I am 

 not acquainted with the shell he describes. It diff'ers also, I conceive, from C. vari- 

 culosum in being much more elongate, and by having a deeper suture, and fewer costae. 

 In C. variculosum there are eighteen costse in the last volution ; in this they are from 

 ten to twelve. In the figures these characters are not sufficiently distinguished. 



6. Cerithium cribrarium. S. Wood. Tab. VIII, fig. 7, a — b. 



Cekithium ceibeakium. S. Wood. Catalogue 1842. 



C. Testa minima, subtdatd, elongatd, tcnui ; anfractibus numerosis, convexis, cingulis 

 quatuor ornatis, longitudinaliter decussatis ; basi Icevi ; canali brevissimo. 



Shell minute, tapering, and elongate, thin, and fragile, with numerous convex 



