566 MR, E. A. SMITH ON SHELLS FROM WEST AFRICA. [NoV. 15, 



3. Notes on three Species of Shells from the Rio del Rey, 

 ; Cameroons. By Edgar A. Smith. 



[Eeceived June 30, 1887.] 



The shells here remarked upon form part of zoological collections 

 recently sent to this country by Mr. H. H. Johnston, H.B.M. 

 Vice-Consul for the Cameroons. 



Ennea (Ptychotrema) cyathostoma, Pfr. 



This species has only been previously recorded from Old Calabar, 

 somewhat to the north-west of the Rio del Rey. Specimens from 

 the two localities offer no differences. 



Melania frethii. Gray. 



The series of specimens in the British Museum and those from 

 the Rio del Rey show that this species varies considerably in form, 

 colour, and sculpture. The typical form (Griffith's Anim. Kingd. 

 vol. xii. pi. 14. fig. 2), from Fernando Po, appears to be identical 

 with M. nigritina, Morelet, found at Gaboon and 'Calabar. M. 

 ffuineensis of Reeve I also believe to be a smoother form of this 

 species ; for although stated by Reeve to be " destitute of any stri- 

 ated or shagreened sculpture," the surface is in fact minutely 

 granosely striated, but much more finely than in the type of M, 

 frethii. The M. foenaria of Reeve is, as suggested by Brot, merely 

 a light-coloured variety, the paleness in a great measure being due 

 to the fact that the outer earthy deposit has been removed from the 

 figured shell (Reeve, Conch. Icon. f. 134). The " zone of reddish 

 rust " described by the author encircles the upper part of the whorls 

 and is frequently visible within the aperture. None of the speci- 

 mens sent by Mr. Johnston are full-grown, and some are very slender, 

 but they all ageee in having three dark bands, clearly seen within 

 the mouth, which would probably become less conspicuous when the 

 shells arrived at maturity. 



Neritina oweniana, Wood. 



Nerita oweniana. Wood, Index Test. Suppl. p. 25, pi. 8. fig. 8. 



Neritina oweniana, Martens, Conch.-Cab. ed. 2, pp. 75, 2/6, 278, 

 pi. 9. figs. 14-17. 



The only locality previously recorded for this species is the island 

 of Fernando Po, which is situated practically in the same region as 

 the Rio del Rey, being only some twenty or thirty miles from the 

 mouth of that river. 



This shell is usually described as reticulated with black ; but 

 among the specimens received from Mr. Johnston are a few which, 

 although reticulated throughout, show distinct transverse dark and 

 lighter zones. The colour of the enamel which overspreads the 

 columellar region varies from an almost uniform reddish tint to 



