Nigerian Eocene Mollusca. 83 



REMARKS. This shell is characterised by its cuneiform contour, its 

 equi-distant, elevated and thin radial costae which anteriorly have their 

 summits ornamented with minute, closely set nodulations, the costae being 

 simple and never showing a divided structure. At first sight this mollusc 

 appears to resemble Cardita aegyptiaca (Fraas) ' from the Lower Eocene 

 (Libyan Beds) of Egypt, as well as C. fayumensis and C. mokattamensis, 

 both of Oppenheim 2 from the Middle Eocene (Lutetian) of the same 

 country. From the first it differs in its more cuneiform contour, the 

 possession of a longer and more oblique posterior margin a slightly larger 

 number of radial costae which are simple and of non tripartite structure. It 

 agrees more closely in contour with the second and third species mentioned, 

 both of which, however, are characterised by their possession of more or less 

 tripartite costae. A resemblance in contour is also noticeable with two 

 limestone casts described by J. Chautard 3 from the Middle Eocene 

 (Lutetian) of Senegal determined as C. sererina and C. baoli, n. spp., 

 although the latter is sufficiently distinct on account of its fewer ribs and 

 being much more inequilateral. I am not familiar, with this type of Cardita from 

 European or Indian deposits and it may perhaps be restricted to African 

 localities. This shell is abundantly represented in the collection. 



OCCURRENCE. Cuttings Nos. i, 2, 5, 6, 10, n, 12, 13, 14, 15. 

 COLLECTOR. Mr. Kitson. 



Gardita triparticostata, sp. nov. 

 PLATE 9, figs. 26-29. 



DESCRIPTION. Shell strong, trigono-cuneiform, inaequilateral, ventricose, 

 length about a quarter in excess of the height, feebly gaping postero-ventrally ; 

 anterior region short, depresso-inflated, with a small smooth cordate lunule 

 surrounded by nodulated costae, posterior end oblique, depressed, lanceolate, 

 smoothly and closely costated, bearing a short and narrow ligament groove ; 

 umbones anterior, approximate ; cardinal elements as in C. costcenodulosis ; 

 sculpture consisting of about 26 broad, radial, tripartite costae, central ray 



1 Aus dem Orient : Wiirttembergis, Nat. Jahres, 1867, Vol. 23, pi. 3, fig. 6, p. 286. 



2 Palaeontographica, 1903, Vol. 30, part 3, pi. 8, figs. 7-11, 13-18, 22-27, PP- 102-105. 



3 Bull. Soc. Geol., France, 1905, Ser. 4, Vol. 5, pi. 5, figs. 4, 5, p. 149. 



6* 



