BIVALVE SHELLS. 223 



Venus, Schrot. Einl. iii. 158. no. 11. 



Cyclas, E71C. Meth. ]). 301. f. 2. 



Cyclas Eupbratica, Lamk. Syst. An. s. Vert. p. 124. 



C\Tena fuscata, var. ?, Lamk. An. s. Vert. v. 552. no. 4. 



Hab. Ex oriente, Lamk. In Euphratico flumine. 



8. CORBICULA AMBIGUA. B.M. 



C. testa ovato-trigona, a^quilaterali, subcordiforrai, transversim 

 dense striato-suloata ; striis regularibus, antice posticeque 

 evanescentibus ; epidermide nitente, nigro-virescenti vestita, 

 in latere postico tenuissime striato-lamellosa, intus violacea ; 

 umbonibus angustis, prominentibus, antice obliquatis ; latere 

 antico atque ])Ostico ffiqualiter convexiusculis, declivibus, ob- 

 tusis ; cardine angusto, dentibus tribus primariis inaequalibus 

 brevibus simjjlicibus, antico valvae dextrae dente laterali ad- 

 nato ; dentibus lateralibus aequalibus, longis extremitate infe- 

 riore leviter arcuatis, crenulato-striatis. 



Corbicula ambigua, Desh. Proc. Zool. Soc. 1854. 

 Hab. Flumen Euphrates. 



d. Species Indicee. 



9. CORBICULA OCCIDENS. B.M. 



C. testa ovato-transversa, aequilaterali, tumida, tenui, transversim 

 regulariter lirato-sulcata ; epidermide flavescente-viridi ves- 

 tita, ad umbones atro-violascente vel breviter albo radiata; 

 umbonibus tumidis, brevibus, lajvigatis ; lunula ovato-lanceo- 

 lata, palhda, Isevigata ; valvis intus j)rofunde fusco-violascenti- 

 bus ; cardine angusto, inaequaliter tridentato ; dentibus latera- 

 hbus brevibus angustis albis tenue striatis. 



Corbicula occidens, Bens. Asiat. Journ. 1824? 



Hab. India ; loco Sikkim dicto, Moredabad, Bengal. Coll. 



Cuming. 



10. CORBICULA BeNSONI. B.M. 



C. testa ovato-transversa, subtrigona, aequilaterali, laevigata, 

 nitida, depressiuscvda, extremitatibus obtusa, utroque latere 

 aequaliter declivi ; epidermidc tenui, nitente, \arescente vel fla- 

 vescente induta, aliquantisper lineis interniptis fuscis radiata, 

 alba vel pallide violascente ; cardine angusto, tridentato, den- 

 tibus inaequalibus valde divaricatis, dentibus lateralibus prae- 

 longis, angustissimis, tenuissime striato-crenatis, antico paulo 

 longiore. 



Corbicula Bensoni, Desh. Proc. Zool. Soc. 1854. 



Hab. In rivuUs Bengalensibus {Benson). Coll. Cuming. 



