PROSOBRANCHIATA. 197 



between the edge and the shoulder is straight, and ornamented with two or three 

 concentric raised lines, very finely granulated. The shoulders bear a single row of 

 prominent, round tubercles, placed at regular and not distant intervals, and continued 

 throughout. The aperture is straight, and very narrow ; the outer lip much arched, 

 and presenting a wide, shallow curvature at the posterior extremity. The concentric 

 furrows cover the whole surface of the young shell, but become more or less effaced as 

 the shell is enlarged, and on the last whorl they are confined to the anterior portion 

 of the shell ; through all stages of growth the basal furrows are deep and sharp- 

 edged. 



A variety occurs at Lee, near Southend, in which the sutural edge and margin of 

 the whorl present four thick, prominent lines, rounded and smooth on the upper surface, 

 and devoid of the granulations which characterise the type. 



I have already noticed the fact, that Bronn has regarded the present species, 

 apparently confined to the lower eocene strata, as identical with the so-called C. ante- 

 diluvianus of Lamarck ; and Dr. Beyrich, adopting that opinion, has applied the name 

 concinnus to a shell from the German Tertiaries which belongs to C. Lamarckii. The 

 narrower form, the smaller number of the volutions, the large rounded tubercles on the 

 shoulders, the more depressed margins of the whorls, with their thickened edges and 

 concentric rows of granulations, or strong elevated lines, and the deep, sharp-edged 

 furrows, barely effaced on the posterior part by the outer coating of the shell, — appear 

 to me sufficiently to distinguish the present shells from those of the middle eocene 

 epoch. I do not agree, therefore, with M. Bronn and Dr. Beyrich, in referring both to 

 the same species ; and in this view, apparently both M. Deshayes and M. D'Orbigny 

 concur. 



Size. — Axis, 1 inch and 3-12ths (32 millim.) ; diameter, rather more than 6-12ths 

 of an inch (between 13 and 14 millim.). 



Localities. — Highgate ; Fortess Green, near Kentish Town ; Lee, near Southend. 

 Mr. Sowerby cites Barton, but I have never met with any specimen from that locality ; 

 and the specimen on the authority of which Barton is cited (' Min. Con./ t. 302, 

 lowest fig.) does not present the characteristic form of C. concinnus ; it is much muti- 

 lated, but it has rather the appearance of a worn specimen of C. scabricidus. M. 

 Deshayes (2d edit, of ' Lam. Hist. Nat.') states that this species occurs in the 

 environs of Paris ; it is not mentioned, however, in his ' Description des Coquilles 

 Fossiles,' and M. D'Orbigny has not given any French locality for it. At present 

 this cone appears to belong exclusively to the earlier eocene fauna. 



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