228 PKOCKEDINGS OF THE MALACOI.OGICAI, SOCIKTY. 



Remarks. — There are two excellent examples of this species in the 

 British Museum with the valves in the closed position, and therefore 

 not exhibiting internal characters. They are of nearly orbicular 

 contour, and would represent the type of the species as figured and 

 described by Etheridge. The valves exhibit a moderate convexity 

 over the uinbonal region, but afterwards considerable compression; 

 they are furnished with a fairly deep lanceolate escutcheon and 

 a short ligament, while beneath the umbones in front is a slightly 

 excavated area, although possessing no true circumscribed lunule. 

 The ornamentation consists of more or less equidistant, flattened 

 growth-bands which are covered with closely arranged, thread-like, 

 concentric striations which are sometimes of slightly irregular design, 

 especially near the ventral margin. 



Type 

 (from largest figiire). New examples. 

 Dimensions. Length . . 34 32 mm. 



Height . .31 30 mm. 



Diameter . . 20 15 mm. 



The specimen figured by Giirich, showing the dentition, which 

 Mr. Etheiidgc, jun., includes under his species opallites, is of far 

 larger dimensions than those mentioned above, and although no exact 

 measurements can be made on account of the fragmentary state of the 

 margins, it probiil)ly was nearly double the size of the largest form 

 represented by Mr. Etheridge's figures ; I have therefore queried its 

 inclusion in this species. 



Locality. — White Cliffs, New South "Wales. 



Collections.— Wii\s\i Museum (Geol. Dept., L. 21273; Mineral 

 Dept., 80065). 



Distribution. — Upper Cretaceous : "White Cliffs, New South "Wales. 



Ctrenopsis adstraliensis, n.sp. PI. VI, Figs. 9, 10. 



Description. — Shell ovate, subtriangular, height less than length, 

 umbones anterior; posterior region elongate, obliquely rounded at 

 margin, with narrow lanceolate escutcheon bearing short ligament; 

 anterior short, slightly excavated beneath the umbones; ventral 

 margins round, and with rounded extremities ; valves moderately 

 convex umbonally, afterwards compressed ; ornamentation consists of 

 equidistant, concentric, periodical growth-bands furnished with fine 

 and closely arranged concentric striations. 



Dimensions {with united valves). — Length 33, height 24, diameter 

 1 1 mm. 



Remarks. — The example described is the largest of three specimens, 

 each of which is in good ])reservation, although no interiors are seen, 

 as the valves are united and closed. The more or less triangulate and 

 suboval contour, together with its anteriorly placed umbones, will 

 suffice to separate this form from C. meeki, with whicli it is otherwise 

 closely related. Among the specimens mentioned is one that has 

 been higlily polished by the lapidary, and is associated on a small 

 ])iece of ferruginously tinted sandstone, with an example of Euspira 

 rariahilis. 



