Zoological Society. 73 



instances more confined and small; where the spot is deepest coloured 

 and largest, the ground on which it is formed is nearly white; poste- 

 rior part of the dorsum irregular, slightly tuberculated, dorsal line 

 marked, nearly white (and in some instances appears both anteriorly 

 and posteriorly to bifurcate), diverging anteriorly towards the colu- 

 mellar side : base white, roundish : aperture rather wide, flexuous, 

 columellar groove on the anterior half of the shell ; the porcelain 

 covering on the gibbous portion of the columella extremely thin ; 

 columella smooth : teeth generally but slight denticulations ; some- 

 times more perceptible on the lip : extremities, posterior, much pro- 

 duced, very obtuse, wide apart, columellar beak divergent; anterior, 

 rather thick, converge at their points towards each other : margins 

 round, light-coloured or white, spotted to the base ; outer margin 

 sometimes uneven, or somewhat nodulated : spire, in all the speci- 

 mens I have seen, quite covered and obliterated : colour, internally, 

 light grayish blue. Axis 1| inch ; diameter 1^ inch. 



Hub. Mocha. In the collection of Mr. Gaskoin, Cuming, &c. 



This shell approximates in general appearance to Cyp. Mus. Some 

 years ago one of this species (leucostoma) came accidentally into 

 my possession, which on comparison I found incompatible with Mtis; 

 and shortly afterwards another, which warranted the distinctive no- 

 menclature. Mr. Sowerby has lately obtained five other specimens, 

 and with them fortunately a knowledge of their locality, which I 

 have quoted. These are now dispersed in the cabinets of Messrs. 

 Harford, (3uming, Stainforth, Norris, and Miss Saul; two others are 

 known to be in the cabinet of Mr. Owen at Manchester. 



This species differs from Mus in being more gibbous ; in the pro- 

 minent and very blunted posterior extremities, the base and aperture 

 being white ; denticulations but very slightly indicated, or absent, 

 and always white. 



I have named this leucostoma, in contradistinction to that which it 

 most nearly resembles, the Cyp. Mus, with its dark-coloured aperture. 



Mr. Fraser exhibited and described a new species of Bat, belong- 

 ing to the genus Rhinolophus, and four new species of Birds from 

 Western Africa. 



Rhinolophus Martini. Rhin. auribus magnis apud frontem inter 

 se spatio aiigusto sejunctis ; rostro fossd oblongd superne, antice 

 quatuor appendiculis camels, vix elevatis (duobus utrinque^, tectd: 

 prosthemate nasali longitudinalitlr diviso ; fossa frontali postice 

 culmine semicirculari dense vellere induto, colUmetutd ; caudd longd 

 et cartilagine bifurcd terminatd ; patagio ad pedes basim solum,' 

 modh ducto : colore cinereo-fusco, subtits canescente. 



unc. lin. 



Long, tot 3 5 



Volatus amplitudo 10 



latitudo maxima 2 4 



Antebrachium 1 6 



Auris 9 



Cauda 1 7 



Hub. Fernando Po. 



