BIVALVE SHELLS. 223 



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



Cyclas, Enc. Meth. p. 301. f. 2. 



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



Cyi'ena fuscata, var. ?, Lamk. An. s. Vert. v. 552. no. 4. 



Hab. Ex oriente, Lamk. In Euphi-atico flumine. 



8. CORBICULA AMBIGUA. B.M. 



C. testa ovato-trigona, seqnilaterali, subcordiformi, transversim 

 dense striato-sulcata ; 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 postico sequaliter convexiusculis, declivibus, ob- 

 tusis ; cardine angusto, dentibus tribus primariis inaequalibus 

 brevibus simplicibus, antico valvar dextrae dente laterali ad- 

 nato ; dentibus lateralibus sequalibus, longis extremitate infe- 

 riore leviter arcuatis, crenidato-striatis. 



Corbicula ambigua. Desk. Proc. Zool. Soc. 1854. 

 Hab. Flumen Euphrates. 



d. Species Indicce. 



9. Corbicula occidens. B.M. 



C. testa ovato-transversa, sequilaterali, turaida, tenui, transversim 

 regulariter lirato-sulcata ; epidermide flavescente-vii-idi ves- 

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

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

 lata, pallida, laevigata ; valvis intus pi-ofunde fusco-violascenti- 

 bus ; cardine angusto, insequaliter tridentato ; dentibus latera- 

 Ubus brevibus angustis albis tenue striatis. 



Corbicula occidens, Bens. Asiat. Journ. 1824? 



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

 Cuming;. 



^e' 



10. Corbicula Bensoni. B.M. 



C. testa ovato-transversa, subtrigona, a^quilaterali, laevigata, 

 nitida, depressiuscula, extremitatibus obtusa, utroque latere 

 sequaliter declivi ; epidermide tenui, nitente, virescente vel fla- 

 vescente induta, aliquantisper lineis interruptis fuscis radiata, 

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

 tibus ina^qualibus valde divaricatis, dentibus lateralibus prae- 

 longis, angustissimis, tenuissime striato-crenatis, antico panlo 

 longiore. 



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



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



