BIVALVIA. 143 
2. Carpita auticostata, S. Wood. Tab. XXI, fig. 3. 
Spec. Char. C. Testa minimd, orbiculari, turgidd, subinequilaterali, radiatim costata, 
costis circa 13 elevatis acutis compressis utrinque nodulosis ; umbonibus minutis, obliquis, 
depressis, subincurvatis ; lunuld minutd. 
Shell small, orbicular, and nearly spherical, nearly equilateral, costated with about 
18 elevated ribs ; beaks small, oblique, depressed, slightly incurved ; lunule small. 
Diameter, 4th of an inch. 
Locality. London Clay, Highgate (dwards). 
One pretty little specimen is in Mr. Edwards’s cabinet, and this appears to me to be 
entitled to a specific position ; its principal distinction is an elevated and compressed sib, 
the lower part of which is angular; on the top of this angle is an elevated ridge, not very 
sharp; on each side of these ridges are some large and distinct nodules, but the centre is 
smooth. 
3. Carpita Bronentarti, Mantell. Tab. XXII, fig. 9. 
Carpita Bronentartu, Mant. Geol. of the South East of Engl., p. 368, 1833. 
= — J. Sow. In Dixon’s Geol. of Suss., pp. 116, 225, t. xiv, 
fig. 33, 1850. 
Spec. Char. C. Testa transversd, irregulariter ovatd, vel oblique subtriangulatd, valde 
mnequilaterali, crassd, tumidiusculd ; siphoni-regione subangulatd ; radialim costatd, 
costts 30—382 depressis, rugosis ; umbonibus subprominentibus lunuld minima profunda ; 
cardine crassiusculo. 
Shell transverse, irregularly ovate or obliquely subtriangular ; very inequilateral, thick, 
slightly tumid, siphonal region roundedly triangular ; costated, ribs about 30, rough and 
depressed ; umbones not prominent; lunule heart-shaped, small and deep; hinge mode- 
rately thick. 
Length, 2 inches ; height, 14 inch. 
Localities. London Clay, Bognor. Var., fig. 12, a, 6, Tab. XXII, Clarendon. 
This species is, I believe, peculiar to England, and it has been long known from the 
locality of Bognor. Mr. Edwards’s cabinet contains also a large suite of specimens from 
Clarendon. ‘This latter shell is here placed as a variety; it differs somewhat in form, 
being less elongated, and has considerable resemblance to planicosta, but it is never so 
large as that species, nor the ribs so flat. Called by Mr. Edwards Clarendonensis. 
