502 ME, H. K. RIDLEY ON THE 



upper portion of it being most prominent ; the tooth above it upon 

 the bocly-wliorl is single, bifurcating at the end. The three re- 

 maining teeth are rather remote from the margin of the aperture. 

 The anterior part of the last whorl just behiud and parallel to 

 tlie labrum exhibits a longitudinal swelling or varix, towards 

 which the lip expands. 



5. STENoamA (Opeas) octonoides, C. B. Adams. 

 Hah. Jamaica, Cuba, St. Thomas. 



This species is more strongly striated than ^S'. subula, has 

 rounder whorls, a deeper suture, and a larger apex. 

 Four specimens were obtained at Platform Island. 



G. Stenogtba (Opeas) subula, Pfeiffer. 



Hah. Cuba, Porto Eico, &c. 



The specimens from Fernando Noronha agree exactly with 

 examples of this species from Porto Eico. They were found 

 beneath stones on the promontory between Clialoupe Bay and 

 S. Antonio Bay. 



7. Stenogtea (Opeas) Beckiaj^a, var. 



Hah. Island of Oj^ara, Peru, Brazil. 



The shells from Fernando Noronha, obtained at tlic same spot 

 as the preceding species, answer w^ell to Pfeifter's description ; 

 but they are more strongly costulatc than Brazilian specimens 

 with which I have compared them. 



III. FEESHWATEIi SPECIES. 



1. Planoebis NOBONHENsis, sp. n. (Plate XXX. figs. 11-11 Z*.) 



Testa parva, valde compressa, superue in medio depressa, 

 iuferne subplanulata, albida, tenui, subpellucida ; anfractus 4, 

 superne convexiusculi, striis incremeuti tenuissimis sculpti, 

 inferne radiatim subplicati, ad suturam angustissime marginati, 

 ultimus infra medium obtuse cariuatus ; peristoma tenue, mar- 

 gmibus callo filiformi junctis, superiore oblique arcuato. 



Diam. maj. 5 millim., min. 4g, alt. 1. 



This species is about the same size and shape as P. Gilberti, 

 Duuker, and P. fragills. Brazier, from Australia. The lower 

 surface, however, is flatter, and the curve of the lip different 



