76 R. BULLEN NEWTON on 



have undoubtedly been subjected to different phases of erosion which has con- 

 siderably diminished certain details of sculpture, such as the marginal serrations 

 of the concentric laminae and the squamose growths of the dorso lateral 

 borders. It is probably one of the flattest forms of the genus yet described, 

 in which respect it comes nearest to the recent species from the Red Sea, 

 Lucina dentifera, Jonas 1 but differing from it in possessing more remote con- 

 centric lamellae in its more compressed valves and being furnished with only one 

 cardinal tooth instead of two. Among fossil forms, from the European Mio- 

 Pliocene strata Liicina orbicularis, Deshayes 2 shows some general affinities 

 although having more convex valves and less remote concentric laminae of 

 growth. The same widely distant laminate sculpture and flattened valves 

 characterise Lucina callipteryx of Tournouer 3 from the French Miocene 

 (Burdigalian), although that species exhibits no squamate extensions on the 

 dorso-lateral margins, no serrated margins to the lamellae, nor is the presence 

 of minute radial striations covering the valves referred to in the original 



O O 



description. Among Eocene forms of this genus, which are mostly furnished 

 with numerous concentric striations and more convex valves, there is Lucina 

 squanmla of Deshayes 4 which bears rather distant lamellae, though they are 

 not dentatecl, nor are there any spines issuing from the dorso-lateral margins. 

 Again, M. Cossmann's Lucina bouryi* from the French Eocene shows 

 squamose projections, on the dorso-lateral margins, but in other respects is 

 easily distinguishable from the Nigerian shell. Reference may also be made 

 to Lucina camerunensis of Oppenheim 6 from the older Tertiary deposits of 

 Camerun, West Coast of Africa, which is related to our species as also to 

 L. jamaicensis of Recent seas, although chiefly differing in its much smaller 

 size, rather closer concentric sculpture and the absence of an antero-lateral 

 angulation. Everything points to the fact that the new form here described 

 presents features connecting it rather with Miocene and Recent species than 

 with those described from Eocene Seas. This shell is included in De 

 Blainville's 7 PJiacoides of which the type is Lucina jamaicensis, Lamarck 



1 R. A. Philippi : Abbildungen Conchylien, 1847, Vol. 2, pi. i, fig. 4, pp. 206, 207. 



2 Expedition de Moree, 1833, Vol. 3, part i, pi. 22, figs. 6-8, pp. 95, 96. 



3 Journ. Conchyl., 1874, Vol. 22, pi. 10, fig. 4, p. 306. 



4 Desc. Coq. Foss., Paris, 1825, Vol. i, pi. 17, figs. 17, 18, p. 105. 



5 Ann. Soc. R. Mai. Belgique, 1887, Vol. 22, pi. 2, figs. 13, 14, p. 38. 



Beitrage Geol. Kamerun (E. Esch.), 1904, pi. 6, figs. 10-14, PP- 260, 261. 

 7 Manuel de Malacologie, 1825, Vol. i, p. 550. 



