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Page 86 



amples are smaller than those from Haiti. A specimen 

 in the British Museum from the latter place is labelled 

 V. circinaria, but it is not Cytherea ci?ri?iata, nor even 

 nearly allied to it. 



When describing Cytherea juncea from Cumana I omit- 

 ted to point out the close kinship between that fossil and 

 C. circinata. 



Chamct involuta n. sp. PI. II, f. 5.* 



Left (attached) valve deep internally, very convex ex- 

 ternally, often spiral, completing a turn and a half, cov- 

 ered externally with distant large foliaceous scales more 

 or less erect, between which are small irregular diverging 

 granose ridges. Right valve patulous, ornamented with 

 numerous close concentric sinuous foliaceous laminae. 

 Umbones, large, prominent, spiral. Margin and laminar 

 cardinal tooth crenate. 



Mr. Vendryes suggested that this might be a Diceras : 

 but I see no ground for referring it to that genus. It is 

 certainly a very spiral chama ; but otherwise its charac- 

 ters are in all respects those of the genus. It is appa- 

 rently always attached by the umbo of the left valve, 

 and the place of attachment is generally marked by the 

 remains or impressions of the septa of corals. It has some 

 resemblance to a recent species found in the Westindies, 

 which if I have identified it correctly is Ck. ?uderalis Lam. 

 but besides other considerable differences the latter is 

 always attached by its right valve. 



Plicatula vexillata n. sp. PI. II, f. j.f 

 Inequivalve, irregularly fanshaped ; valves, usually with 

 the disk almost smooth, adorned towards the margin by 7 

 or 8 stout obtuse radiating ribs along each of which are 

 disposed a few lines of reddish brown (probably red when 



[^Geological Magazine, vol. n, 1874, pi. 17.] 

 [t " " vol. ii, 1874, pi. 17.] 



