Cretaceous Gastropoda, and Pelecypoda from ZuUdand. 31 
PELECYPODA. 
Family AECIDiE. 
Genus CUCULL^A, Lamarck, 1801. 
Syst. Anim. sans Vert., 1801, p. 116. 
CucuLL^A wooDsi, sp. nov. 
Plate IV., figs. 4-9. 
Description. — Shell sub-quadrate, thick, inflated, slightly inaequi- 
lateral; umbonal region elevated, arched, obtusely and obliquely 
carinated posteriorly with extension to the postero-ventral angle ; 
anterior margin short, rounded and obtusely angled at the hinge ; 
posterior region oblique, deep, vertically sided, obtusely angled at 
the hinge, and medianly ridged in the young state ; ligament-area 
moderately wide, lanceolate, with from four to five thin, angulate 
sulcations which deflect outwards from beneath the umbo of each 
valve ; hinge thick, lower margin slightly curved, bearing about eight 
small central nearly vertical teeth and four or more elongate, oblique 
teeth on each side ; ornamentation consisting of numerous obscure, 
radial striations, crossed by prominent, rugose concentric lines of 
growth within which is a finer and closer series of concentric ridges 
separated by very narrow grooves. ' - 
Dimensions. — 
Left Valves. Small specimen 
Large. Medium. with closed valves. 
Length 50 42 25 mm. 
Height 52 45 25 „ 
Diameter 30 23 22 „ 
Observations.— ^hi^ species shows a relationship to Parkinson's 
C. glabra (Organic Eemains, 1811, vol. 3, p. 171) from the Black- 
down beds, although certain differences exist which seem to require 
the separation of the two forms. The valves from Zululand are 
distinctly more oblique, they are shorter posteriorly, and the length 
and height are of nearly similar dimensions. A greater convexity is 
also apparent, so that when both valves are united they present a 
more or less globular appearance ; the dentition differs also in 
structure, inasmuch as the lateral teeth are inclined to obliquity and 
not so horizontal or parallel with the hinge margin as generally 
observed in the English species ; and lastly, the shell sculpture 
appears to be of a coarser design. 
