Cretaceous Gasiroiooda, and Pclccypoda from Zulidand. 73 
Family YENEEIDiE. 
Genus VENUS, Linnaeus, 1758. 
Systema Naturae, 1758, edition x., p. 684. 
Venus, sp. 
Plate VL, figs. 10-1^. 
Description. — Shell globose, thick, length and height about equal ; 
umbones contiguous, antero-central, incurved ; lunule cordiform, 
wide, well defined; posterior end broad, circumscribed in the cast 
by an obtuse keel on each side curving gently from the umbones to 
the ventral region, and which would represent in the shell an elongate 
groove running obliquely from beneath the umbo to the antero-basal 
margin of the posterior muscular scar ; sculpture consists of con- 
centric ridges and sulcations in close and regular arrangement 
ornamented with numerous microscopically fine vertical striations. 
Dimensions (specimen with closed valves). — 
Length 40 mm. 
Height 40 ,, 
Diameter , 30 
Observations. — Unfortunately, there is only one example of this 
shell in the collection, which is so very fragmentary that the 
posterior half is stripped of its testiferous structure, a reddish-brown 
matrix beneath filling the valves and so forming an internal cast of 
the posterior region. Parts of both valves are, however, preserved, 
these being united and in the closed state ; the anterior area, 
especially of the left valve, is well covered' with a strong, robust 
shell material showing a thickness of 2 mm. The umbones are 
obscure and imperfect, though their incurved character can just 
be seen, beneath being the wide and well-defined lunule, this being 
succeeded by a prominently rounded margin which is continued to 
the ventral border. The tumidity of the valves and their well- 
sculptured sides, together with the broad posterior end makes this 
a singularly striking shell, but the absence of dental characters 
creates a difficulty as to its true generic position, although the tout 
ensemble compares favourably with that of a modern Vemis, such as 
the rugosa of Chemnitz, which is furnished with similarly tumid 
valves, a concentrically ridged ornamentation, a prominent lunule, a 
short rounded anterior region, besides an extensive and well-curved 
posterior margin. The sculpture of the present shell also agrees 
with that characterising J. de C. Sowerby's Veiius caper ata from the 
Blackdown beds [= Albian) of England, but this latter has more 
depressed valves, besides being of a lighter and more delicate 
