S T R yE A. 



Plate XXII. 



Species 51. (Mus. Taylor.) 



OsTR^A LACERANS. Oft. tcstA elongato-suhtrigond, 

 longitudinaliter attemiatd, tenui, foliaced, pallida, 

 inlus purjiureo tinctd ; ad marginem veidralem 

 lobatd, cardine trigono, producto ; valvd supenori 

 depressd, suhconcavd ; valvd inferiori costis acutt's, 

 imbricatis, subspini/eris, distantibiis sculptd. 



The torn Oyster. Shell elongate subtrigonal, longi- 

 tudinally attenuated, thin, foliaceous, pale, tinted 

 inside with purple, lobed 'at the ventral margin ; 

 hinge trigonal, produced ; upper valve depressed, 

 rather concave ; under valve sculptured with 

 sharp, imliricated, and rather spiniferous distant 

 ribs. 



Hanlev. Proc. Zuol. Soc. 1845. 



Ilab. Senegal. 



Species 52. (Fig. a, b, Mus. Brit.) 

 OsTRiEA. glomerata. Ost. testd crassd, irregulari, acuti- 

 costatd, margine dentaio vel lobato, valde inoiqui- 



valvi, valvd superiori opercidari compressd, laminis 

 eraitsis concentricis fugatA ; valvd inferiori cucul- 

 latd, purpured, intils albidd, purpurea aut nigra 

 marginatd ; mnrginibus l(deralibun denticulatis, 

 cardine plemmque attenuato, producto, acuminata. 

 The conglomerated Ostr^a. Shell thick, irregu- 

 lar, sharp-ribbed, with the margin dentated or 

 lobed, very inequivalve ; upper valve opercular, 

 compressed, wrinkled with thick concentric 

 lamina; ; lower valve cucullated, purple, while 

 witliin edged with purple or black ; latera mar- 

 gins denticulated ; hinge generally attenuated, 

 produced, pointed. 

 GdULD. AVilkes' Expedition. 



Hab. ? 



It is ditScuIt to distinguish this species from Ostriea 

 cucullata, if indeed they be not identical. The ribs of 

 0. glomerata are more numerous and strong, not 

 broadly angular as in Fig. o4, a, b. The young are 

 often spinose as in Fig. 52, b. Never, perhaps, so much 

 so as in the true 0. spinosa. 



September, 1871. 



