70 
Bulletin 35 
218 
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 circinata, nor even 
near!}' allied to it. 
When describing Cytherea jimcea from Cumana I omit- 
ted to point out the close kinship between that fossil and 
C. circinata. 
Chama involuta n. sp. PI. II, f. 5.* 
Left (attached) valve deep internall}-, ver\’ convex ex- 
ternalljL 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. Vendr^'es suggested that this might be a Diceras : 
but I see no ground for referring it to that genus. It is 
certainh" a verj' spiral chama ; but otherwise its charac 
ters are in all respects those of the genus. It is appa- 
rentl}' always attached by the umbo of the left valve, 
and the place of attachment is generallj' marked b}' 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 Ch. tnderalis Lam. 
but besides other considerable differences the latter is 
always attached by its right valve. 
Plicatula vexillata u. sp. PI. II, f. y.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 
dispo.sed a few lines of reddish brown (probably red when 
[■^Geological Magazine, vol. ii, 1874, pi. 17.] 
[t “ “ vol. II, 1874, pi. 17.] 
