Nigerian Eocene Mollusca. 77 



from the North Atlantic. The species is named after Sir John Eaglesome, 

 one of the collectors and donors of these Nigerian fossils now in the 

 British Museum. 



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

 COLLECTOR. Mr. Kitson. 



Phacoides subrhomboidalis, sp. nov. 

 PLATE 7, figs. 4, 5. 



DESCRIPTION. Shell subrhomboiclal, inaequilateral, plano-convex, length in 

 excess of height, anterior side smallest ; dorsal margins sloping posteriorly, 

 short and horizontal in front, dorsal-lateral areas compressed, slightly flexuous, 

 obtusely angulate ; ligament furrow deep, elongate, narrow ; lunule forming a 

 narrow sulcation to the dorso-lateral obtuse angle ; lateral borders more or less 

 vertical, notched in the centre, ventral margins elongately curved, nearly 

 horizontal ; valves covered with closely-set elongate, concentric lamellar striations 

 with a few distant radial grooves on the dorsal areas. 



DIMENSIONS. 



Height ... ... ... ... ... 37 millimetres. 



Length ... 45 



Diameter (closed valves) ... ... ... 17 



REMARKS. Unfortunately this species is represented by only one specimen 

 which has closed valves so that internal characters are not observable. The 

 fossil is, however, in good preservation and may undoubtedly be referred to 

 De Blainville's Phacoides (type = Lucina jamaicensis, Lamarck, North 

 Atlantic), which includes those Luciniform shells having a more or less lenti- 

 form shape, strong- dorsal areas, and a generally concentric sculpture. The 

 relations of the present shell are closest to Bellarcli's Lucina pharaonis x from 

 the Eocene of Egypt, which according to Oppenheim 3 embraces L. bialata 

 and L. aegyptiaca both of Bellardi, and both, also, from the Egyptian Eocene 

 deposits. There are, however, certain distinctions which tend to separate the 

 new shell from the Egyptian form. The Nigerian specimen has considerably 



1 Mem. R. Accad. Sci. (Torino), 1854, Ser. 2, Vol. 15, pi. 2, fig. 12, pp. 190, 191. 

 - Paleontographica, 1903, Vol. 30, part 3, pi. 13, figs. I, 2, pi. 15, fig. 6, pp. 124-128. 



