Cretaceous Gastropoda, and Pelecypoda from Zulidand. 43 
whereas in aliformis the front portion of the anterior region possesses 
the thicker and more distant costse, a series of closer and much 
thinner costae occupying the remaining surface to the postero- 
ventral angle. A fragmentary left valve is also referred to this 
form, showing considerably worn pallial costse, a well-ornamented 
escutcheon surface bearing delicately transverse granulated costellaB 
of great regularity, and an umbonal convexity, which is more 
accentuated than in the right valves just described. Although 
this Trigonia appears to have a close association with T. scabra it 
must be remarked that its contour is rather more rostrated posteriorly 
than is the usual form of that species ; it, however, belongs to 
x\gassiz's group of the Scabrse, of which T. aliformis may be regarded 
as the type, its horizon being probably recognised as Cenomanian or 
Albian ; the true scabra being characteristic of Cenomanian times, 
whilst the aliformis belongs more particularly to the Albian stage of 
the Cretaceous series. The Indian examples of T. scabra figured by 
Stoliczka are said to be found in the Trichinopoly and Ariaylur 
Cretaceous groups. 
Locality. — North end of False Bay. 
Family MZTILID^. 
Genus LITHOPHAGA, Bolten, 1798. 
Museum Boltenianum [Hamburg], 1798, Part 2, p. 156. 
Synonym — Litliodomus, Cuvier, 1817. 
LiTHOPHAGA MANUANENSIS Sp. nOV. 
Plate IV., figs. 1-3. 
Description. — Shell elongate, sub-cylindrical, convex ; anterior 
end rounded, posterior cuneiform, dorsal line slightly curved; 
latero-ventral areas compressed; umbones moderately inflated, 
incurved, nearly marginal ; ornamentation consisting of rugose, 
rather distant, concentric growth-lines. 
Dimensions (specimen with closed valves). — 
Length 30 mm. 
Height 13 „ 
Diameter 14 ,, 
Observations. — This description applies to a single specimen with 
closed valves having a considerably fractured test, yet preserving 
certain elements of structure which are of importance in respect of 
its determination. The specimen is somewhat longer than the 
generality of Cretaceous forms of this genus, and the valves show a 
