66 
Transactions of the Boyal Society of South Africa. 
with regard to Syria. The forms described and figured, however, 
considerably differ from the Zululand specimen both in point of 
contom^ and in the ornamentation of the valves. So far as can be 
ascertained, no specimens of this genus have been recorded from 
Natal or other Cretaceous localities of Southern Africa. 
The species is named after Mr. William Anderson, F.G.S., the dis- 
coverer of the fossils forming this collection, and who at that time 
was Government Geologist of Natal. 
Locality. — Tributaries of the Manuan Creek. 
Description. — Specimen consisting of an upper valve exhibiting an 
obliquely orbicular contour with a generally depressed external 
surface but with a slightly concave ventral margin ; the apex and 
lower part of the right lateral border are not preserved. The 
sculpture shows well-marked concentric growth-lines crossed by 
six or seven very slightly convex radial costae which emanate from 
the umbonal region, though a good deal obscured before reaching 
the ventral border. The costae broaden out in front, as do the 
shallow grooves which separate them, whilst the extreme one to 
the right appears to be bifurcated. Internally the specimen is 
furnished with a broad, smooth, rounded margin, the inner border 
of which, forming the pallial line, bears a single row of small, distant 
tubercles placed at almost equal distances apart and extending from 
the dental region throughout this circumscribed portion of the valve. 
A large circular eccentric adductor scar-marking is also present, as 
well as the remnants of two distant cardinal teeth projecting from 
each side of the dental area, which are divided by a worn excavated 
space. 
Dimensions, — 
Observations. — It is difficult to institute a comparison when only 
one valve is available for study, but incidentally it may be mentioned 
that on account of its few cost£e there is a resemblance to 
P. paucicostata of Sequenza from the Turonian-Cenomanian series 
of Southern Italy {Atti B. Accad. Lincei [Eoma] , 1882, vol. 12, 
ser. 3, pi. 15, fig. 7, p. 170), but in that form there is a more 
elongate outline, and moreover the costae extend to the ventral 
margin and set up a plicated character which is absent in the 
Plicatula eogersi, sp. nov. 
Plate II., figs. 13, 14. 
Length 
Height 
Thickness of shell structure 
(about) 30 mm. 
(about) 35 
