Nigerian Eocene Mollusca. 21 



strong and irregular spiral costae of which the two upper nearly touch and 

 form a pair, while the third is further removed and followed to the end of 

 the canal by a series of nearly equi-distant spiral costae which are more or 

 less obscure. The strong spiral costae are, therefore, confined to the anterior 

 walls of the volutions while the finer spiral sculpture, composed of more regular 

 striations, characterise the ornamentation of the wide posterior surfaces, and 

 are particularly significant on the earlier whorls. Neither the type of this 

 species as figured by Mayer-Eymar nor Oppenheim's example exhibit any- 

 thing like perfect sculpture characters, and it can only be imagined that erosive 

 agencies have removed some of the finer and more delicate ornamentation 

 from those specimens. It was thought at first, by the present writer * that 

 Mayer-Eymar 's species from Egypt might include Cltnuropsis diderrichi of 

 E. Vincent 2 from the Paleocene beds of the Belgian Congo, no very important 

 differences seeming to separate the two forms, although, from their closer 

 study it now seems advisable to keep them distinct, because the whorls of 

 the Congo shell appear to be more depressed and less excavated, the peripheral 

 tubercles are nearer to the suture, while the general aspect of the spire is 

 more funnel-shaped or pagodiform rather than turreted. The possession of the 

 very marked sinuated labrum in both species would at once suggest their 

 reference to H. & A. Adams' Surcula, which was founded on Murex javanus 

 of Linnaeus (= Lamarck's Pleiirotoma nodiferd] from the Indian Ocean. M. 

 Vincent, however, placed the Congo species under the then new generic name of 

 ClinuropsiS) his type being Pleurotoma ampla of Briart and Cornet 3 from 

 the Paleocene ( = Montian) of Belgium, and moreover, recognised it as 

 possessing Fusoid characters resembling Buccinofusus. The presence of the 

 sinus and other details do not appear to favour such a classification, Clinuropsis 

 being here considered a true Surcula and therefore, belonging to the family 

 of the Turridae. Further forms related to S. ing-ens would include : Pleu- 

 rotoma keelei of F. E. Edwards 4 from British older Eocene deposits; 



1 R. B. Newton : Abst. Proc. Geol. Soc. London, 1919, No. 1042, p. 102. 



2 La Faune Paleocene de Landana (Mollusques) : Ann. Mus. Congo Beige, 1913. Ser. 3, Vol. I, Geol., 

 p. 21, pi. 2, figs. 8-1 1. 



3 Mem. Cour. Acad. R. Sci. Belgique, 1871, Vol. 36, pi. 4, fig. 8, p. 51 ; ibid., 1880, Vol. 43, pi. 15, fig. 7, 

 p. 28. It should be mentioned that Pleurotoma ampla is regarded by M. Cossmann under Dr. Ball's 

 Ancistrosyrinx but since that genus has never been figured, so far as can be ascertained, it can only 

 be referred to as of doubtful value Essais Paleoconch. Comp., 1896, part 2, p. 71. 



4 Mon. Palaeontographical Soc. 1856, pi. 26, fig. 6, p. 219. 



