172 Annals of the South African Museum. 



specimen (No. 136). There are 5-6 cardinal spines on each side,, 

 their bases only in most cases being preserved. The surface is- 

 covered by fine closely set ribs, increasing by bifurcation and inter- 

 calation to about 130-140 round the margin. The pedicle valve has 

 a triangular inclined hinge-area. 



Another larger specimen (No. 127), probably belonging to the 

 same species, consists of the internal cast of a pedicle valve with 

 submucronate angles, a median septum about one-third the length of 

 the valve, strong flabellate diductor impressions, and the surface 

 covered with punctae betweeii the fine ribs, which seem to be similar 

 to those in No. 136. There is no median depression in the valve as 

 Morris and Sharpe describe. 



These specimens, however, may both be referred without much 

 doubt to Ch. falklandicus, and they are very closely allied if not. 

 identical with Ch. comstocki Hartt,* as Von Ammon {ojJ. cit.) has 

 remarked of this species. The European form Cli. sarcinulat^is 

 belongs also to the same group. It seems questionable if Kayser's 

 Ch. falklandicus f from Argentina is rightly identified. 



Dimensions. — (No. 127) Length 17 mm. ; width 32 mm. (No. 136} 

 Length 11 mm.; width 21 mm. 



Localities. — (No. 136) Near Ceres Village, along the Valsch Elver. 

 (No. 127) Hartebeeste Kraal, Ceres. 



CHONETES cf. COEONATUS Conrad. 



(Plate XX., figs. 11, 12 ; Plate XXI., figs. 1, 2.) 



Amongst the numerous species in this collection referable to- 

 the genus Chonetes there is one which seems to resemble closely 

 Conrad's Ch. coronatus of the Hamilton Group. There are specimens 

 (Nos. 112, 118) showing internal casts of both the brachial and 

 pedicle valves. The shell is transverse or semi-elliptical in shape, a 

 little wider than long, with a straight hinge-line equal to or rather 

 less than the greatest width of the shell, and the cardinal angles are 

 rectangular or slightly rounded. The pedicle valve is moderately 

 convex with a shallow undefined median longitudinal depression, 

 and the lateral angles somewhat flattened ; the beak rises above the 

 hinge-line and is slightly incurved ; the hinge-area is narrow, inclined 

 and triangular, with the foramen partly occupied by the prominent 

 cardinal process of the brachial valve. The brachial valve is flattened 



• Eathbun, Bull. Buffalo Soc. Nat. Sc, i., 1874, p. '250, pi. ix., tigs. 5, 14, 18,. 

 19, 31. 



t Kayser Zeitschr. deut. Geol. GeselL, xlix., p. 299, t. x., tig. '2. 



