140 EOCENE MOLLUSCA. 
have a greater curve, especially in the pedal region. The ribs are rounded, and about as 
broad as the spaces between them, and the exterior appears to have been slightly pustular, 
both over the ribs as well as between them. ‘The valves are united, and the specimen is 
not in good condition. (The engraved figure is slightly enlarged.) 
3. Verticorpta suncata, J. Sowerby. Tab. XXI, fig. 9, a, d. 
IsocarpIa suLcaTA, J. Sow. Min. Conch., tab. 295, fig. 4, 1821. 
— — Morris. Catal. Brit. Foss., p. 204, 1854. 
Spec. Char. V. Testé minimd, orbiculari vel spheroided, tumidd, inflatd, tenui, valde 
inequilaterali, radiato-costulatd, costulis convewiusculis ; umbonibus magnis obliquis in- 
curvatis ; lunuldé parvd, profundd, ovata ; marginibus crenulatis. 
Shell small, orbicular, or rather spheroidal, tumid, and inflated, thin, very inequilateral, 
with radiating and somewhat curving ribs; beaks large, obliquely incurved ; lunule small, 
deep, and ovate; margins crenulated. 
Diameter, 7’sths of an inch. 
Localities. London Clay. Potter’s Bar and Sheppey (dwards), Whetstone and Chalk 
Farm (Wetherell). 
A few specimens only of this species have as yet been found, although they are dis- 
tributed through several localities. These unfortunately have the two valves united, so 
that the interior has not yet been seen. 
The shell is very tumid, and with the valves united is nearly spherical; the riblets or 
costula appear to have been nearly convex; but there is so little of the true shell or 
exterior remaining, that I am unable positively to say what was the correct shape of these 
ribs; the spaces between them appear to have been about the same breadth; the umbo 
tumid and prominent, with the beaks much inflexed and very excentric, curving over a 
deep lunular depression. Pyritous casts are also found at Sheppey. 
1. Verticorpra propinaua, S. Wood. Tab. XXI, fig. 7. 
‘The specimen from which my figure is taken is merely a cast; it comes from the 
cabinet of Mr. Edwards, and, from its possessing a larger number of ribs or riblets and 
being more oblique in outline than any of the other species, I have presumed it to be 
distinct. It is from a cutting in the London Clay at Highgate. The name is, however, 
provisional, and it is figured for the purpose of calling attention to its existence. 
The nacreous composition of these shells seems to have been unfavorable to their 
preservation. 
