Mr. R. J. L. Guppy onneto Species of Bivalve }f()Uusrn. W) 



\ I. — On new Species of Bivalve Molbisca found at Cnmana, 

 Venezuela. \\y R. J. Leciimere Guppy, F.L.S., F.G.8., 

 &c. 



[Plate VI I. figs. 1 & 2.] 



One of tlie shells now to be described is a large and fine 

 species of Venus. If I mistake not, this species has been 

 regarded by some as the V. crcnulata of Chemnitz ; but the 

 shell which I have for years considered to be that species is a 

 smaller and very different one. 



The other shell is a Mactrn, not belonging to the typical 

 group of that genus, but, on the contrary, somewhat of an 

 aberrant form. It is a large and interesting species. 



The recent, not less than the fossil, shell-fauna of Cumana 

 is very interesting. Among the recent shells are several 

 which are by no means common in the West Indies — as, {«r 

 instance, the true Persona reticularis (^Linn.), which, though 

 nearly allied to, must not be confounded with the P. dathrata 

 of Madagascar nor with the fossil P. simillima of the West- 

 Indian Miocene. Dipsacus glabratus occurs at Cumana ; and 

 I have also from that place an undetermined species of Fusus 

 (which resembles young shells of Fasciolaria (jif/antea, except 

 that it has a longer canal), and also the following — Solarium 

 tessellatuin, Pkos (juadelupensis^ Venus fexuosa, Cahjptrcea 

 auriculata (of which apparently there is a good figure in the 

 large edition of Cuvier's 'R^gne Animal,' pi. 48. f, 4, under the 

 name of C Cuvieri, Desh.), Oliva reticularis (several forms), 

 and 0. monilifpraj Reeve (?=;0. mufica, SRy, = nitidula). 



Venus superha, n. sp. PI. VII. fig. 2. 



Ovate, slightly subtrigonal, a little inequilateral, ventricose ; 

 anteriorly produced and rounded ; posteriorly ]iroduced and 

 subangulate ; umbones closely approximate ; lunule large, 

 striated with irregular diverging lamellae, distinctly defined 

 by a sharp groove ; posterior dorsal area large, striate, not 

 distinctly defined. Valves marked with numerous irregular 

 angulate streaks of chestnut or brown, and adorned with 

 numerous concentric crenate ribs, which are rather more distant, 

 thinner, and more distinctly crenate near the anterior and 

 posterior margins ; on the disk the ribs are square, flattened, 

 and polished, and the crenation is less marked. Length 70 

 millims., height 55, thickness about 45. 



Mactra anserina, n. sp. PI. VII. fig. 1. 



Oval, compressed, subequilateral, gaping widely posteriorly j 

 Ann. d' }fa(]. N. ITisi. Ser. 4. Vol. xv. 4 



