KXOTIO UMOMU.i: ,^y 



distinctly the disposition to biangiilarity of the posterior portion of the valves, and 

 here the marks of growth shew some greenness, which is no where else observable. 

 In more perfect specimens some of these characters may be found to be very different. 

 It is to be regretted that there should be only a single one, and that very imperfect 

 in the beaks and some parts of the epidermis. 



In outline this species is near \ofnrhJens, Ben., but it is not so obliquely triangular. 

 It may easily be distinguished by its lighter colored epidermis, and by its having 

 a much thinner substance of the valves, the ponderosity being very different, as well 

 also by the cardinal and lateral teeth being very much thinner and less crenulate. 

 In outline it has some resemblance to some of the oblique varieties nf ohh^miM, Lam., 

 but the cardinal teeth are totally different in character. 



U.vio Wtnegungaensir. pi. 45, fig. 151. 



.Testa Ijevi, pliiptiea. inflata, inppquilaterali. postict' subbianorulata, antic^ oblique i-otundata ; vaivulis 

 subcra.ssis, antip^ crassioribus ; natibus prominentibus, ad apices vald^ divaricate undulatis ; epider- 

 mide luteo-oliva, micante, obsolete radiata ; "dentibus cardinalibus anbcrassis, suberectis, vald^ crenu- 

 latis, in utroque valvulo duplicibti.s ; latoralibns sublnnfris, crassis siihrectisqup : mar^arita salmonis 

 colore paulisper tineta et iridescpiitc. 



Shell smooth, elliptical, inflated, inequilateral, somewhat biangular behind, ob- 

 liquely rounded before ; valves rather thick, thicker before ; beaks prominent, very 

 . undulate and divaricate at the tips ; epidermis yellowish olive, shining, and obso- 

 letely rayed ; cardinal teeth rather thick, somewhat erect, very much crenulate and 

 double in both valves; lateral teeth rather long, thick and nearly straight: nacre 

 light salmon color and iridescent. 



f.'nio Wi/rwgungnenais, JiCa. Proc. Acad. Nat. Sci., 1859, p. 331. 



5fl&.— Wynegunga River, thirty miles east of Nagpoor, in the Deccan, Bengal. 

 C. M. Wheatley. 



My cabinet and cabinet of Mi-. Wheatley. 

 I^if^ni- I5 Length 1-5, Breadth 24 inches. 



Shell smooth, elliptical, inflated, inequilateral, somewhat biangular behind and 

 obliquely rounded before ; substance of the shell rather thick, thicker before ; beaks 

 prominent, very much undulated, with divaricate and zigzag undulations at the tips ; 

 ligament rather long and thick ; epidermis yellowish olive, shining, obscurely rayed, 

 with distant marks of growth and disposed to be transversely banded ; umbonial slope 

 raised and rounded ; posterior slope rather depressed, rather wide, with a dark line 

 from the beaks to the posterior margin in each valve and ti'aversing a number of 

 small oblique folds ; cardinal teeth rather thick, somewhat erect, very much crenu- 

 late and double in both valves ; lateral teeth rather long, thick and nearly straight ; 

 anterior cicatrices distinct and very deeply impressed; posterior cicatrices di.stinct 

 and very slightly impressed ; dorsal cicatrices placed on the under side of the plate 



