Zoological Society. 289 
Osrrea tacerata, Ost. testd elongatd, solidiusculd, valde in- 
aquivalvi, haud lamellosd, ad nates acutas angustatd, ad latera 
basimque laceratd ; valvuld superiore planulatd, sublevigatd, aut 
lutescente radiis sordide rubro-purpureis ornatd, aut rubro-pur- 
ured radiis duobus centralibus nigrescentibus aream angustam 
albidam includentibus ; valvuld inferiore profundd, radiis latis 
atropurpureis strigatd, costisque raris subangulatis armatd ; super- 
ficie internd albidd, submargaritaced ; cardine denticulis nullis 
munito. Long. 2 poll. 
Hab. Senegal? Mus. Petit, Cuming. 
_ Not unlike parasitica, but distinguishable by its claw-like lateral 
projections. I have never met with any valves attached by the en- 
tire surface. The dull crimson specimens, adorned with two central 
dusky rays, which usually enclose a narrow space of yellowish white, 
are peculiarly beautiful. 
Osrrea MULTIsTRIATA. Ost. testd suborbiculari, compressd, equi- 
valvi, solidiusculd aut subtenui, viv lamellosd, brunneo-rufescente, 
confertissime radiatim rugosd ; superficie internd valvule superi- 
oris nived, purpureo marginatd; inferioris disco centrali rufo 
pulcherrime tinctd ; cardine dentibus validis munito ; natibus haud 
eminentibus ; cicatrice satis magnd. Long. 3°3 poll. 
Mus. Saul, Cuming, Hanley. © 
The lower valves were attached by their entire surfaces to a ship 
returning from the coast of Africa. 
Ostrea Mrcopon. Ost. testd falcatd, glabra, solidd, subequi- 
valvi, pallide livido-purpurascente, margines versis plicatd ; plicis 
anticis 5 aut 6, maximis, subangulatis ;,posticis minimis, angulatis, 
paucis, subobsoletis ; margine valde plicato, intusque magis minusve 
scabro ; natibus incurvatis ; superficie internd albo-virescente, nun- 
guam margaritaced ; cicatrice satis magnd, reniformi. Long. 5 poll. 
Hab. Peru (Cuming). Mus. Cuming. 
A rare and extraordinary species, which bears not the slightest 
resemblance to any of the recent Ostree. The narrow sickle-shaped 
contour and the gigantic marginal tooth-like folds form its most di- 
stinctive characteristics. ‘Che adult specimens are attached by their 
apices only. 
Osrrea Pzs-tieris. Ost. testd ovali, aut ovali-subtrigond, solidd, 
concolore, atro-purpureo aut rubro-purpurascente, undique sub- 
lamellosd, ad margines dense plicatd ; lamellis imbricatis, confertis, 
depressis; plicis regularibus, rotundatis ; valvis in longitudine 
paribus ; inferiore profundd, superiore planulatd atque in costas 
planas sulcis latis remotis radiatim divisd; superficie internd 
albidd, margine interno denticulato ; denticulis elongatis ; cicatrice 
satis magnd, obovali aut suborbiculari. Long. 2 poll. 
- Hab. Isle of Luzon; on rocks (Cuming). Mus. Cuming, Walton. 
In typical specimens the shell is subtriangular, from the anterior 
side sloping in a produced and straightish line, abruptly from the 
beaks. The sculpture is both elegant and peculiar, the extremely 
depressed ribs being divided by rather broad grooves, and assuming 
