CUCULL AA. al 
1898. CucuLitza (IponEarca) Cornveviana, EF. G. Skeat and V. Madsen. Dan- 
marks geol. Undersog., vol. 11, 
p. 167, pl. vi, fig. 5. 
? Non 1846. Anca (CucuLLz,) Cornuetrtana, A. FE. Reuss. Die Verstein. der bohm. 
Kreidetormat., pt. 2, p. 13. 
Description.—Shell more or less oblong, convex, a little inequilateral. Anterior 
border forming an angle (90° or more) with the hinge-line, gradually curving 
toward the ventral border. Ventral border curved. Posterior border nearly 
straight, oblique, forming a rounded angle with the curved ventral border. 
Umbones of moderate size, close together; no distinct carina, but the shell is 
sharply bent along a line passing from the umbo to the postero-ventral angle ; 
this flattened part is divided into two nearly equal parts by a narrow carina passing 
from the umbo posteriorly; on the right valve the carina is thread-like and 
crenulated; on the left valve it is less sharply defined. Area small, narrow. 
Ornamentation consists of numerous fine concentric ribs or striw, and radial 
ribs usually less distinct than the concentric, but well marked anteriorly. Hinge- 
line relatively long. Central teeth transverse; lateral teeth parallel to the hinge- 
margin, striated. 
Measurements : 
(1) (2) (3) (4) 
Length . , : ; : fDi, 20°5 38 28 mm. 
Heicht . y ; : ; . 22 21 32 25) «,, 
Thickness. : : : . 19 20 — — , 
Afjinities.—This species is closely related to C. glabra, Parkinson (see p. 57), 
but it never attains such large size, and its average is much smaller. It varies 
considerably in the proportion of length to height ; in some eases the valves are 
only a little longer than high—in this respect differing from the type. Many forms 
are proportionately longer than is ever the case with C. glabra. The umbones are 
less prominent and less pointed than in the latter species. Arca Robinuldina, 
d’Orbigny, differs from this species in possessing a sharply defined carina, &e. 
I am inclined to think that the three specimens from Upware (preserved in 
the Woodwardian Museum), which were referred by W. Keeping (vide supra) to 
C. subnana, Pictet and Roux, belong to C. Cornueliana. 
Types.—I did not find the types in the d’Orbigny Collection. 
Distribution.—Crackers and Lower Crioceras Group of Atherfield. Bed xiv of 
Blackgang Chine (fide Fitton). Atherfield Beds of East Shalford. ? Lower 
Greensand of Upware. 
