The Cretaceous Fauna of Pondoland. 293 



posterior part of the area is nearly smooth except for growth-Hnes. 

 The whole of the escutcheon bears transverse costellae. 



Length 53 . 43 . 35 mm. 



Height 43 . 32 . 29 „ 



Affinities. — T. Shepstonci shows some resemblance to the Indian 

 forms of T. scahra, Lamarck, figured by Stoliczka,'" but is readily 

 distinguished by its area, by the finer costellae on the escutcheon, 

 and by the fewer and more spiny tubercles on the costae. 



The area and escutcheon in T. Shepstonei resemble those of 

 T. crenulata, Lamarck, f but in the former the costae are less 

 numerous and bear fewer tubercles, and the anterior costae cut 

 the front margin more obliquely. 



i?e7?iar /cs.—Griesbach's Fig. 11a does not give a correct im- 

 pression of the characters of this species. The costae are much 

 more prominent, and the concentric arrangement of the tubercles 

 is much less distinct than they appear in that figure. The posterior 

 part of the valve is also incorrectly drawn ; the area is really much 

 larger and the posterior costae smaller and more obhque. 



The originals of Griesbach's Figs. 11, lib, and lie are in the 

 Hamburg Museum. The original of Fig. lla appears to be missing, 

 but a note with the Hamburg specimens states that " probably the 

 figure is constructed from several specimens." In the original of 

 Fig. 11 the valves are gaping, so that the shell is not quite so convex 

 as appears at first sight from the figure. 



Fifteen specimens have been examined. 



Trigonia elegans, Baily. 

 Plate XXXV., figs. 3, 4. 

 1855. Trigonia elegans, Baily, Q.J.G.S., xi., p. 461, pi. xiii., fig. 3. 

 Description. — Shell ovately trigonal, somewhat produced pos- 

 teriorly, moderately convex with flattened sides. Greatest con- 

 vexity is along a line drawn from the umbo ventrally. Anterior 

 marginal part of the valve curves rapidly and becomes vertical to 

 the plane between the valves, or is sometimes even bent inwards. 

 This curvature decreases in passing along the ventral margin in a 

 posterior direction. The whole of the margin of the valve anterior 

 to the umbo forms a regular and considerable curve and passes 

 gradually into the ventral margin, the curvature of which decreases 



* Cret. Fauna S. India (1871), p. 314, pi. xv., figs. 24-26, pi. xvi., figs. 35-40. 

 t For references see Woods, Mon. Cret. Lamell. England, vol. i. (1900), p. 82. 



