CANALIFERA. MOLLUSCA. CERITHIUM. 275 



Cerithium Emersunii. 



Shell long-conical, chestnut- colored ; whorls seventeen, fiat, each 

 encircled with three series of granules ; canal less than halj the 

 length of the aperture. 



Figure ISO. 



State Coll., No. 276. See. Cab., No. 2361. 



Cerithium Emersonii, Adams ; Bosi. Journ. JVaf. Hist., ii. 284, pi. 4, f. 10. 



Shell small, conical, elongated, glossy, reddish-brown, with a 

 regularly granulated surface ; whorls sixteen or seventeen, flat- 

 tened, with a revolving series of bead-like granules at the upper 

 and lower margins of each, and another intervening one, but 

 nearer to the upper than to the lower series, and less prominent, 

 commencing at ten or twelve whorls from the summit, and be- 

 coming more distinct as it approaches the base ; in each series 

 the granules are connected by a rather narrow, but elevated re- 

 volving line, nearly as high as the granules ; they are also con- 

 nected in a similar manner in a longitudinal direction ; posterior 

 edge of the whorls margined by a sharp ridge, of a darker color ; 

 suture profoundly impressed ; the ridge terminates abruptly before, 

 in a very short, twisted, wrinkled beak ; aperture small, about 

 one sixth the length of the shell ; outer lip scolloped when per- 

 fect. Length I inch, breadth ^ inch, divergence 22°. 



Obtained by Professor C. B. Adams, at Nantucket and in New 

 Bedford harbour, by whom it was described and named in honor 

 of G. B. Emerson, Esq., President of the Boston Society of 

 Natural History. 



This prettily sculptured shell is distinguished by its short aperture 

 and beak, its broad base, from which the flattened whorls regularly 

 taper to an acute apex ; and by the pi'eily strings of bead-like gran- 

 ules encircling it. These beads are sometimes so worn down as to 

 present the appearance of a continuous line dilating at regular in- 

 tervals. 



This shell is unequivocally pronounced by Mr. Sowerby to be the 

 Murex tubercularis of Montagu. But, after a careful examination of 

 all the descriptions of that shell, I am led to conclude, either that I 



