CYRENA. 



25 



Cyrena cordlformis, Recluz, (preoc.) II. ConcL. IV, 1853, 251, pi. 

 vii, f. 9. 

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

 cabinet of Mr. Cuming. Mr. Kecluz does not assign any locality 

 to it, but I am satisfied on careful inspection that it comes from 

 Central America. Compared with C. infiata, it is heavier, more 

 inflated and more heart-shaped. 



•->o. Cyrena cumineii, Deshates.— Shell ovate-subtrigonal, in- 

 equilateral, tumid, heart-shaped; anterior side short, broadly rounded; 

 posterior side longer, truncated at extremity ; beaks large, prominent, op- 

 posite, approximate at apex, eroded ; valves rather solid, interior white ; 

 ^triffili-ht and irregular; epidermis brownish-green; hiuge-margin nar- 

 row somewhat broad in the centre; cardinal teeth approximate, narrow, 

 unequal, bifid ; lateral teeth large, equidistant from the cardinal teeth, 

 anterior tooth larger, conical, acute. 



Long. 2.40 ; Lat. 2.03 ; Diam. 1.76 inches. 

 4, (30 • " 52 ; " 44 mill. 



Hah. Central America. (Cabinet of Cuming.) 



Cyrena cumingii, Deshayes, Proc. Zool. XXII, 1854, 22. 

 ^ rare shell, the only specimen I have met with is the one in 

 Mr Cuming's collection. Compared with C maritima, it diifers 

 in having an epidermis, in being larger, transversely more elon- 

 gated and less inflated. 



23. cyrena isocardioides, DESHAVEs.-Shell orbicular-subtri- 

 .onal, inflated, heart-shaped, light, fragile; anterior side a regular and 

 broad semicircle; posterior side forming on the upper part a dechvi y, 

 subtiuncated at extremity; stria light, irregular; epidermis ohve-color 

 with zones of black; beaks large, curved inwards, opposite, tinted with 

 violet ; hinge-margin very narrow ; cardinal teeth very small, aPP-^-^t^' 

 Bubeqial, the two anterior ones parallel, the posterior divergent; lateral 

 tLth small, situated at about the same distance from the cardinal teeth; 

 valves white inside, with markings of violet on the margins. 

 Lons. 2.16 ; Lat. 2.12 ; Diam. 1.60 inches. 

 u" 54 ; " 53 ; " 41 mill. 



Hah. South America, in Western Columbia. (Cabinet of Cuming.) 



Cyrena isocardioides, Desh. Proc. Zool. XXII, 1854, 22. 

 A rare species, the onlv specimen I have seen is the one in Mr. 

 Cuming's collection; it presents great affinity to C. recluzu m 



