392 
Guppy Reprint 
91 
/70 
artistic skill for the execution of such work is not to be found 
here. The figures are only intended to give, in conjunction 
with the descriptions, a fair general idea of the shells wished 
to be represented, and it should not be supposed that they 
are meant for finished drawings. 
§ 2. The Species of Nuciila ajid Leda. 
I. Niicula schomburgki. Forbes (PI. vii., f. 10.) 
N. schomburgki, Forbes, in Schomburgk, History of 
Barbados, p. 565. 
N. schomburgki Guppy, Geol. Mag., 1867, p. 500. 
The likeness of this shell to N. bivirgata, N. ornatissima, 
and N. cobboldies was remarked by Prof. Forbes when 
describing it. and he gave the greater w'eight to its alliance 
with the latter. Nevertheless, to me it appears more nearly 
allied to A', bivirgata. The recent species of the small group 
of divaricately ornamented Nuculas, in which the above 
extinct species find their place, are N. castrensis and N. 
divaricata. Eocene, Barbados, Trinidad (Sanfernando). 
2. Nucula crosbyana n. sp. (PI. vii, f. 3, 3a). 
Oval-elliptical, sub-equilateral, .scarcely attenuated behind, 
thin, smooth, shining, indistinctly marked by some close 
concentric riblets, more visible towards the regularly curved 
ventral margin ; ends rounded, slightly gaping, the anterior 
end the shortest, forming an angle wuth the hinge-line ; 
umbones small, scarcel}" prominent; hinge-teeth about twelve 
before the ligamental pit and about fifteen behind it. Length, 
16 mm. ; height, 8^ mill. 
I received from Mr. W. O. Crosbj" two dead valves of this 
species, dredged by him in the Gulf of Paria. In shape it is 
