BIVALVE SHELLS. 251 



angustis, inaequalibus, majoribus profunde furcatis, lateralibus 

 inaequalibus, corapressis, antico majore. 



C)Tena incerta, Desh. Proc. Zool. Soc. 1854. 



Hab. ? CoU. Cuming. 



29. Cyrena Essingtonensis. B.M. 

 C. testa ovato-suburbiculari, subtriangulari, ina^quilaterali, trans- 



versim striata, striis inaequalibus, epidermide viridi-fuscescente, 

 postice nigrescente vestita ; antico latere breviore rotundato, 

 superne leviter arcuato, declivi, postico paululum angustiore ; 

 cardine angusto, inajqualiter tridentato, dentibus j)rominen- 

 tibus apice profunde lissis, basi coarctatis, subpediculatis, den- 

 tibus lateralibus parvis, antico majore conico, fossula valvuhe 

 dextrai profunda, superne canaliculata, dente cardinali ejusdem 

 valvulaj oblique prorainente. 

 Cyrena Essingtonensis, Desk. Proc. Zool. Soc. 1854. 

 Hab. Portus Essingtoniensis [Cuming). CoU. Cuming. 



30. Cyrena Jukesi. B.M. 



C. testa ovato-trigona, turgidula, insequilaterali, transversim ir- 

 regulariter striata, epidermide nitida flavicante pallide vires- 

 cente et brevissime laminata vestita, latere antico brevi, su- 

 perne fere reetilineo, declivi, postico rotundato, superne con- 

 vexiusculo ; valvis intus albis, umbonibus minimis, brevibus, 

 antice obliquatis ; cardine angusto tridentato, dentibus sub- 

 aequalibus, duobus raajoribus apice bifidis, angustis, lateralibus 

 subsequalibus, conicis, compressis. 



Cjrrena Jukesi, Desh. Proc. Zool. Soc. 1854. 



Hab. Caput Upstai-t dictum Australise septentrionalis. 



c. Testa suborbicularis. 



31. Cyrena suborbicularis. B.M. 



C. testa suborbiculari, valde intequilaterali, alba, sub epidermide 

 viridi regulariter concentrice lamellata, apicibus ])rominulis, 

 integris; margine dorsali utroque rotundato, postico anticum 

 sesquies scquante, ventrali valde arcuato ; dentibus cardinalibus 

 ternis, binis bifidis ; lateralibus brevibus, lajvibus. {Phil.) 



Cyrena suborbicularis, Phil. Abbild. Conch. p. 7. pl. 2. f. 1. 



Hab. Manilla. 



