26 AMERICAN CORBIcrLADJE. 



shape and bulk ; it differs, however, in beiug very much less heavy 

 and solid ; the hiuge-margiu is narrower and the teeth are smaller 

 and slighter. 



24. Cyreiia tumida, Prime. — Shell trigoual, inflated, equilateral, 

 somewhat solid ; anterior margin convex, obtuse, subangular ; posterior 

 margin convex, presenting a declivity on the upper part, angular, sub- 

 rostrated ; inferior margin ventricose ; epidermis dark ; beaks very small, 

 depressed, opposite ; hinge-margin narrow ; cardinal teeth small, narrow, 

 the two larger ones bifid ; lateral teeth unequal, compressed, the anterior 

 one lai'ge, acute, triangular ; valves white in the interior with a rosy hue. 



Long. 1.36; Lat. 1.20; Diam. 0.80 inches. 

 " 3-1; " 30; " 2U mill. 



Hah. Central America. (Cabinet of Cuming.) 



Cjjrena angulata, Desh. (preoc.) Proc. Zool. XXII, 1854, 22. 



The only specimen I have seen of this species is the one in the 

 collection of Mr. Cuming. 



25. Cyreiia pilllastra, MIJrch. — C. testa ovalis, tenuis, albescens, 

 radiatim subtilissime striata, valde inaequilateralis, convexiuscula, antice 

 brevissime angustata, postice late rotundata, niargo dorsalis anticus preei- 

 pite declivis, posticus rectus fere horizontalis, postice angulo obtuso ; 

 margo ventralis parum arcuatus ; area postice violacea tincta ; dens late- 

 ralis posticus valvse sinistra remotissimus, compressus, inter laminas 2 

 valvfe dextrre receptus ; dens anticus subapproximatus ; sinus syphonalis 

 angustissimus, sursum spectans. 



Long. 30; Lat. 23 mill. 



Hah. Central America, at Real ejo in Nicaragua. (Cabinet of Morch.) 

 Cyrena {Polymesodd) pullastra, Mi3KCH, Malak. Bl. VII, 18G0, 194.) 



I have not been able to identify this species. I know of no 

 Cyrena from Realejo to which the above description would apply. 



26. Cyrena inflata, Philippi. — C. testa ovato-trigona, valde tu- 

 mida, tenui, irregulariter transversim striata, epidermide olivaceo-nigres- 

 cente vestita ; extremitate postica elongata ; apice subtruncata ; margine 

 ventrali parum arcuato ; apicibus valde prominentibus, involutis, decorti- 

 catis ; dentibus cardinis lateralibus integris, in valva dextra abrupte ter- 

 minatis ; paging interna alba. 



Long. 28}'"; Alt. 26J'"; Crass. 21J'". 

 Hab. Central America, in Costa Rica. (Cabinet of v. d. Busch.) 

 Cyrena injlata, Philippi, Zeit. Malak. 1851, 71. 



