565 
Order-ARCACEA, 
Pamily — ARCIDA2. 
Genus — CTTOULL^A, Lamarch, 1801. 
(Syst. Anim. .sans Verteb., p. 116. ) 
CrcuLLiEA EOBUSTA, Etheridge, PI. 26, figs. 1 and 4. 
Cucullcea rolusta, Etheridge, Quart. Jmirn. Geol. Soc., 1872, xxviii., p. 340, t. 20, f. 1. 
,, costata, Etheridge,. lilt'd., t. 20, f. 2. 
S^}. Char. Shell trapeziform or rhomhoiclal and nearly equilateral ; body of the 
Talves very convex and inflated ; dorsal margin straight, long ; area wide and flat ; 
posterior teeth three or four, horizontal crests of the teeth and bottoms of the sockets 
denticulated ; ventral margin rounded, closed, the interior wide and flattened ; anterior 
and posterior ends truncated ; umbones large, gibbous, distant, and incurved ; pallial 
line straight ; costas or ribs thirteen to twenty-four in number, equal, sharp, composed of 
from three to five subordinate ribs, the posterior end apparently devoid of ribs ; inter- 
spaces wide, filled with very fine riblets parallel to the principal costae. 
Obs. It is very questionable if two species exist at Maryborough, where these 
shells appear to be moderately common. I have therefore combined both for the present 
under one name. 
The ribs, or costae, become wider apart towards the extremities of the valves, and 
are sharp with wide interspaces. The latter are filled with very fine riblets, and the 
whole surface is well cancellated by sub-imbricating frills. The usual number of 
principal costae is thirteen, three on the anterior end and the remainder confined to the 
body of the shell, the posterior end being apparently devoid of them, or at any rate 
with the costae very faintly developed. Between each pair are four or five smaller or 
secondary costae, besides the five lines previously mentioned. 
Gucullcea virgata, J. de C. Sby.,* from the “ Upper Secondary ” Formation of 
Cutch, is remarkably like C. rohusta, both in shape and ornament. 
Log. Maryborough {The late B. Baintree')-, Corporation Quarry, Maryborough 
{VF. H. Bands ; Messrs. T. W. E. Bavid and G. Sweet — Colins. David and Sweet). 
Family— NUCULID^. 
Genus — NTTCULA, lamarch, 1799. 
(Prodrome — Mem. Soo. Hist. Nat. Paris, 1799, p. 87.) 
NucriA QUAUEATA, Etheridge, PI. 26, figs. 8 and 9. 
^ucuta quadmta, Etheridge, Quart. Journ. Geol. Soc., 1872, xxviii., p. 341, t. 19, f. 6, t. 20, f. 3. 
Sp. Char. Shell quadrate and tumid, umbones anterior, and anterior side short 
and vertical ; posterior side much elongated and sharply rounded ; teeth on posterior 
side large and numerous ; those on anterior side few (seven or eight) and smaller ; 
posterior dorsal margin flat. {Etheridge.) 
Obs. This and the following species appear to be unusually large for Cretaceous 
forms. The muscular scars and pallial line are very strongly marked in the cast. In 
one of Mr. Etheridge’s original figures of this species the scars of the retractor ("f) 
muscles, usually met with on the visceral region of the interior surface of Nuculm, are 
exceedingly developed, and give to the surface of the cast quite a pock-marked 
appearance. It is a rather thick, heavy species, with fifteen or sixteen posterior, very 
large hinge-teeth. 
* Trans, Geol. Soc., 2nd Ser., v., E.xpl. t. 22, t. 22, f. 1. 
