COSBICULA. 5 



Long. .37 ; Lat. .37 ; Diam. .25 inch. 

 &quot; 10 ; &quot; 10 ; &quot; 7 mill. 



Hob. South. America, in the Surinam River, Guyana. (Cabinets of the 

 Academy of Natural Sciences of Philadelphia and Prime.) 



Corbicula rotunda, PRIMED Pr. Acad. Nat. Sc. Ph. 1860, 80. 



The only specimens I have seen of this species, those in Phila 

 delphia and those in my own collection, are so worn that it is not 

 possible to form any correct idea of the color of the epidermis, nor 

 of the interior markings. Compared with C. paranensis it is 

 more trigonal, longer from the beaks to the basal margin, trans 

 versely less broad and more inflated. It differs from C. convexa 

 in being smaller, less rounded, higher and less inflated. 



5. Corfoicula limosa, DESHAYES. Shell transverse, ovate-ellipti 

 cal, inequilateral, compressed, somewhat tumid, com 

 paratively solid, anterior side narrower, posterior Fig. 4. 

 shorter, subtruncated ; striae irregular ; epidermis 

 greenish ; valves rather strong, inside white or of a 

 deep violet ; beaks tumid, inclined towards the inte 

 rior ; hinge-margin broad, with three unequal teeth ; 

 cardinal teeth diverging, the principal ones bifur 

 cated ; lateral teeth nearly equal in length, narrow, G Mimosa. 

 serrulated ; palleal impression terminating posteriorly 

 in a small trigonal sinus. 



Long. .87; Lat. .68 ; Diam. .50 inch. 

 &quot; 22 ; &quot; 18 ; &quot; 13 mill. 



Hab. South America, in the rivers of Eastern Uruguay. (Cabinets of 

 the British Museum, Smithsonian Institution, Cuming and Prime.) 



Tellina limasa, MATON, Trans. Linn. Soc. London, X, 1809, 325, pi. 24, 



f. 8-10. 



Cyrena limosa, GRAY, Ann. Ph. n. ser., IX, 1825, 137. 

 Cyre.no, variegata, D ORBIGNY, Guer. Mag. V, 1835, 44. 

 Cyclas variegata, D ORBIGNY, Voy. Amer., 1846, 567, pi. 82, f. 14-16. 

 Cyclas limosa, D ORBIGNY (error), loc. sub. cit. 1846. pi. 82, f. 14-16. 

 Corbicula semisulcata, DESHAYES, Proc. Zool. XXII, 1854, 343. 

 Corbicula limosa, DESHAYES, Biv. Brit. Mus. 1854, 231. 



This well-marked species varies much in general appearance ; 

 some specimens are beautifully marked with light brown rays run. 

 ning from the beaks towards the basal margin, others do not ex 

 hibit these markings. The epidermis of the young shell is very 



