Mr. R. J. L. Guppy on new Species of Bivalve Mollusca. 49 
VI.—On new Species of Bivalve Mollusca found at Cumana, 
Venezuela. By R. J. LecuMere Guppy, F.L.S., F.G.8., 
&e. 
[Plate VII. figs. 1 & 2.] 
One of the 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. crenulata 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 Mactra, 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, for 
instance, the true Persona reticularis {Linn.), which, though 
nearly allied to, must not be confounded with the P. clathrata 
of Madagascar nor with the fossil P. s¢millima of the West- 
Indian Miocene. Dipsacus glabratus occurs at Cumana; and 
I have also from that place an undetermined species of /usus 
(which resembles young shells of Fasciolaria gigantea, except 
that it has a longer canal), and also the following—Solarium 
tessellatum, Phos quadelupensis, Ve 
‘ nus flexuosa, Calyptrea 
auriculata (of which apparently there is a good figure in the 
large edition of Cuvier’s ‘Régne Animal,’ pl. 48. f. 4, under the 
name of C. Cuviert, Desh.), Oliva reticularis (several forms), 
and O. monilifera, Reeve (? =O. mutica, Say, =nitidula), 
Venus superba, n. sp. Pl. VII. fig. 2. 
Ovate, slightly subtrigonal, a little inequilateral, ventricose ; 
anteriorly produced and rounded; posteriorly produced and 
subangulate ; umbones closely approximate; lunule large, 
striated with irregular diverging lamelle, 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. Pl. VII. fig. 1. 
Oval, compressed, subequilateral, gaping widely posteriorly ; 
Ann. & Mag. N. Hist. Ser. 4. Vol. xv. + 
