Nigerian Eocene Mollusca. 67 



examples are in a good state of preservation, the radial striations being 

 generally present on both valves or at any rate on the grooval surfaces 

 between the costae. 



DISTRIBUTION. The Upper Mokattam beds of Egypt, and the Priabonian 

 rocks of Italy. 



OCCURRENCE. Cuttings, Nos. 5 and 12. 

 COLLECTOR. Mr. Kitson. 



Family PINNID^E. 

 Pinna, sp. 



REMARKS. Some thin fragmentary layers of shell structure are the only 

 relics available to indicate the presence of the genus Pinna in the Nigerian 

 rocks. These are friable and very delicate although of interest from their 

 markings which exhibit more or less regular, nearly equi-distant, longitudinal 

 costae, together with obscure evidence of distant and obliquely concentric 

 growth-lines ; parts of the shell surface show also small irregularities of 

 sculpture which assume a malleated appearance. Although it is difficult to 

 restrict such ornamentation to any particular species without the study of 

 complete specimens, there is a suggestion among these fragments that they 

 may have belonged to an elongate-trigonal form resembling P. margaritacea 

 of Lamarck 1 from the British and European Eocene (Barton and Bracklesham 

 Beds), more especially as the longitudinal costae and the obliquely-curved 

 striations agree with Searles Wood's 2 figure of that species as well as with 

 some well-preserved examples from the Paris Basin. It is to be regretted 

 that these remains should be somewhat inadequate for purposes of exact 

 specific determination. 



OCCURRENCE. Cutting No. 10. 

 COLLECTOR. Mr. Kitson. 



1 Ann. Mus. Hist. Nat. (Paris), 1805, Vol. 6, p. 218 ; ibid., 1807, Vol. 9, pi. 15, fig. 8. 



2 Mon. Pal. Soc., 1861, pi. n, fig. 9, p. 56. 



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