290 Zoological Society, 



a scalloped appearance at their edges, from the crowded sublamellar 

 imbrications which cover the entire surface. 



OsTREA BicoLOR. Ost. tcstd ohovutd, nunquam elongatd, subtenui 

 aut soUdiusculd, subcompressd, vix lamellos.d, purpureo-fuscescente 

 radio uno vel radiis duohus albidis ornatd ; margine simplici ; 

 natibus subacutis ; superficie internd, albidd colore externo rkargi- 

 natd ; cardine denticulis nullis munito. Long. 2\ poll. 

 Hab. Senegal.'' Mus. Cuming, Hanley. 



As the few specimens I have yet examined of this elegant species 

 have been attached by the entire surface to the sheathing of vessels, 

 I am unable to describe the characteristics of the lower valve. The 

 lamellae, when existing, are flattened, so that the shell presents a 

 smooth surface, and appears inclined to expand laterally whenever 

 unobstructed in its growth by adjacent substances. 



OsTREA coLUMBiENSis. Ost. testd sublncequivalvi, subtenui, lamel- 

 losd, albidd, purpurea radiatd, subcompressd ; valvuld inferiore 

 magis convexd; superficie internd albidd, submargaritaced ; car- 

 dine denticulis nullis munito; cicatrice satis magnd, renifoimi. 

 Long. 2 poll. 

 Hab. St. Elena, West Columbia, adhering to rocks at half-tide 

 (Cuming). Mus. Cuming. 



All the specimens I have seen are attached by the entire surface 

 of the lower valve. The shape varies from oblong to suborbicular, 

 and the valves are of equal length, but the shelly substance of the 

 shallow upper valve fits into the lower one, and is only continued to 

 the margin by the lamellae, which, when the habitat permits, branch 

 into wavy foliations. 



OsTREA Callichroa. Ost. tcstd obovatd aut suborbiculari, soUdius- 

 culd, subcequivalvi ; valvuld superiore purpurea alboque lutescente 

 radiatd, concentrice lamellosd ; lamellis depressis ; valvuld inferiore 

 magis minusve purpurea tinctd, costisque radiantibus subobtusis 

 dense armatd ; superficie internd, albd ; margine simplici ; cardine 

 denticulis distinctis munito. Long. 2 poll. 

 Hab. Island of Chiloe, adhering to stones at low-water mark 

 (Cuming). Mus. Cuming. 



The general appearance is that of our edible oyster, but the colour- 

 ing is magnificent. 



October 28.— George Gulliver, Esq., F.R.S., in the Chair. 



A paper was read containing ** Descriptions of new species of 

 Shells," by Lovell Reeve : — 



MuREX MACULATUS. Mur. tcstd ovtttd, subpyramidali, anfractibus 

 brevibus, tuberculato-varicosis, varicibus interstitiisque subtiliter 

 liratis, liris, lirarum interstitiis quaque pulcherrime fimbriato- 

 cancellatis ; albidd, maculd rubido-fuscd inter varices conspicue 

 tinctd ; columelld et aperturcE fauce pallide rosaced ; canali bre- 

 viusculo, recurvo. 



Hab, ? 



