Cretaceous Gastropoda, and Pelecypoda from Zululand. 71 
Natal and Zululand," 1907, pi. 3, figs. 1, 2, p. 79), although, according 
to Mr. Etheridge's figure 2, the posterior slope does not appear to 
be so steep as in the present specimen, which has a width of 
20 millimetres. The softer and more marly deposits of the Manuan 
Creek district have also yielded a fragmentary specimen of this 
species which must have been of similar size to the foregoing, the 
posterior area having a width of 20 mm. The external sculpture of 
this example is in excellent condition. 
Some small adherent Annelids (see p. 97) are present on the 
lateral face of the large cast, having a diameter of '5 mm. They 
may be mentioned as of circular outline, flattened, composed of five 
or six contiguous volutions and resembling a Cretaceous form from 
New Jersey, described and figured by Morton as Vermetus rotula 
(Synopsis of the Organic Eemains of the Cretaceous Group of the 
United States, 1834, pi. 1, fig. 14, p. 81). 
An adherent Polyzoan should also be observed on the external 
surface of the left valve, which appears to belong to the genus 
Memhranipora (see p. 96). 
The species is named in honour of Mr. E. Etheridge, Curator of 
the Australian Museum, Sydney, and author of some valuable reports 
on the palaeontology of Zululand. 
Locality. — Tributaries of the Manuan Creek. 
Family MACTEIDiE. 
Genus MACTEA, Linnceus, 1767. 
Systema Naturae, 1767, edition xii., vol. 1, p. 1125. 
MaCTRA (?) RUPERT-JONESI, Sp. nOV. 
Plate VI., figs. 16, 17. 
Description. — Shell transversely oval, inflated, thick, nearly equi- 
lateral; anterior margin rounded; posterior region wide (23 mm.), 
deep, oblique, obtusely angulate from umbo to postero-ventral 
angle, outer margin truncate ; umbonal region elevated, ventricose, 
curved ; lunule apparently wide, shallow, not properly defined ; 
ornamentation consisting of fairly closely arranged concentric 
striations divided by rather coarser and somewhat distant periodical 
growth-lines. 
Dimensions (specimen with closed valves). — 
Length . . 
Height .. 
Diameter 
47 mm. 
