BIVALVE SHELLS. 245 



10. Cyrena LAUTA. 



C. testa ovato-transversa, subtriojona, inaequilaterali, superne 

 inferneque convexiuscula, postice subtruncata, antice valde 

 declivi, rectilinea, crassa, solida, in medio convexa ; epidermide 

 fusca, nitida, tenue irregulariter striata ; umbonibus depressis, 

 brevibus, apice acutis, approximatis, s;epius erosis ; lamina 

 cardinali lata, dentibus cardinalibus tribus obliquis, angustis, 

 elongatis, approximatis, fere parallelis, superne canabculatis, 

 antico valva; dextrse dimidia i^arte breviore ; dentibus laterali- 

 bus subajqualibus, postico valde remoto. 



Cyrena lauta, Desh. Proc. Zool. Soc. 1854. 



Hab. ? 



11. CyRENA SIMILIS. 



C. testa ovato-trigona, oblonga, ina^quilaterali, in medio tumida, 

 transversim distaiiter striata, epidermide fuscescente, ferrugi- 

 nea nitente vestita ; umbonibus minimis decorticatis ; latere 

 antico brevi, rotundato, obtuso, latere postico superne con- 

 vexiusculo, declivi, sensim atteuuato, extremitate breviter sub- 

 truncato ; dentibus tribus, pnmariis duobus subaequalibus apice 

 inaequaliter bifidis ; dentibus lateralibus minimis, antico valvae 

 sinistrse conico, depressiusculo, postico longiore. 



Cyrena oblonga, Desh. Proc. Zool. Soc. 1854. 



Hab. Manilla. Coll. Cuming. 



12. Cyrena affinis. 



C. testa oviformi, ovato-transversa, infcquilaterali, ventricosa, 

 crassa, solida, epidermide tenui,fusco-ochracea laevigata induta, 

 transversim ina^qualiter striata, subcontabulata ; umbonibus 

 minirais, depressis, integris, vix prominentibus, latere antico 

 brevi, late rotundato, postico attenuato, obtuso ; cardine an- 

 gusto, dentibus tribus angustis, duobus majoribus profunde 

 canaliculaiis ; dentibus lateralibus a^qualibus, antico acutius- 

 culo, postico valde remoto. 



Cyrena affinis, Desh. Proc. Zool. Soc. 1854. 



Hab. Australia (Cuming). CoU. Cuming. 



13. Cyrena oviformis. 



C. testa ovato-transversa, crassa, solida, turgida, inaequilaterali, 

 transversim irregulariter incrementis striata ; area lunulaque 

 laevigatis, epidermide tenui, brunnea vel flavescente vestita ; 

 antice brevi, declivi, obtusa, postice magis attenuata ; latere 



