Zoological Society. 2ft9 



OsTREA LACERATA, Ost. testd elongtttil, solidiusculd, valde in- 

 cequivalvi, hand lamellosd, ad nates acutas angustatd, ad latera 

 hasimque laceratd ; valvuld superiore planulatd, sublceoigatd, aut 

 lutescente radiis sordide rubro-purpureis ornatd, aut rubro-pur- 

 pured radiis duobus centralibus nigrescentibus aream angustam 

 albidam includentibus ; valvuld inferiore prqfundd, 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. 1 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. 



OsTREA MULTisTRiATA. Ost. testd suborUculari, compressd, eequi' 

 valvi, solidiusculd aut subtenui, vix lamellosd, brunneo-rufescente, 

 confertissime radiatim rugosd ; super jicie internd valvules 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 Megodon. Ost. testd falcatd, glabrd, solidd, subaqui- 

 valvi, pallida livido -purpuras cent e, margines versus plicatd ; plicis 

 anticis 5 aut 6, maximis, subangulatis ; poslicis minimis, angulatis, 

 paucis, subobsoletis ; margine valde plicato , intusque magis minusve 

 scabro ; natibus incurvatis ; superficie internd albo-virescente, nun- 

 quam 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 OstrecB. The narrow sickle-shaped 

 contour and the gigantic marginal tooth-like folds form its most di- 

 stinctive characteristics. The adult specimens are attached by their 

 apices only. 



Ostrea Pes-tigris. Ost. testd ovali, aut ovali-subtrigond, solidd, 



concolore, atro-purpureo aut rubro-purpurascente, undique sub- 



lamellosd, ad margines dense plicatd ; lamellis imbricatis, con/ertis, 



depressis ; plicis regularibus, rotundatis ; valvis in longitudine 



paribus ; inferiore profundd, superiore planulatd atque in castas 



planas sulcis latis remotis radiatim divisd; superficie internd 



albidd, margine interna denticulate ; 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 sub triangular, 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 



