258 DESCRIPTION OF NEW 



Unio rufusculus. PI. XIV. Fig. 7. 



Testa Isevi, elliptica, subcompressd, inxquilaterali, postice biangulatd; valvulis subcrassibus ; natibus sub- 

 prorninentibus ; epidermide tenebroso-fuscd, striata ; dentibus cardinalibus obliquis, parvis striatisque; laterali- 

 btts remotis, longis, lamellatis, rectis; margaritd vel alba vel sahnonis colore tinctd. 



Shell smooth, elliptical, rather compressed, inequilateral, biangular behind; valves rather thick; beaks some- 

 what prominent; epidermis dark-brown, striate; cardinal teeth oblique, small and striate; lateral teeth remote, 

 lono-, lamellar and straight; nacre white or salmon coloured. 



Hab. Abbeville District, S. C. J. P. Barratt, M. D. 

 My cabinet. 

 Diam. .9, Length 1.4, Breadth 2.4 inches. 



Shell smooth, elliptical, rather compressed, inequilateral, biangular behind, rounded 

 before, substance of the shell rather thick, thicker before ; beaks somewhat prominent and 

 submedial ; ligament rather long and thick ; epidermis dark-brown, obscurely rayed on the 

 posterior slope, striate towards the margin, with obscure, nearly equidistant marks of 

 growth ; umbonial slope subangular ; cardinal teeth oblique, small, with regular striae ; 

 single in the right and double in the left valve; lateral teeth separated from the cardinal 

 tooth, long, lamellar, straight, and slightly thickened towards the posterior end; anterior 

 cicatrices distinct; posterior cicatrices confluent; dorsal cicatrices placed rather above 

 the centre of the cavity of the beaks; cavity of the shell rather shallow; cavity of the 

 beaks very small; nacre white or salmon coloured. 



Remarks. — This species belongs to the group of which the common U. complanatus is 

 the type. It seems to stand between it and U. Congarcnus, (Nobis.) It is more angular 

 on the umbonial slope than complanatus, and less so than Congaraus. Of the three speci- 

 mens received, two are salmon coloured. The oldest specimen is very thick and much 

 eroded. The youngest is rather thin. The outline of this species is very much like the 

 figure of Unio pkmi/atcris, Conrad, but it differs in the colour of the epidermis, in the 

 thickness of the teeth, and the obliqueness of the umbonial slope. It is also very like 

 U.fulvus, (Nobis,) which also came from South Carolina; and it is possible that when 

 good suites are brought together, this species may prove to be only the adult of a flatter 

 variety of fulvus. 



Unio Whiteianus. PI. XIV. Fig. 8. 



Tcstd Isevi, elliptica, inflatu, valde inxquilaterali, postice subangulatd ; valvulis crassis; natibus subpromi- 

 ncntibus; epidermide vel tenebroso-fuscd vel nigra, striata, ad apices politd; dentibus cardinalibus magnis, 

 elevatis, crenulatis ; lateralibus longis subewvisque; margaritd vel alba vel satmonis colore tinctd. 



Shell smooth, elliptical, inflated, very inequilateral, subangular behind; valves thick; beaks somewhat promi- 

 nent; epidermis dark-brown or black, striate, towards the beaks polished; cardinal teeth large, elevated, crenu- 

 lated ; lateral teeth long and somewhat curved ; nacre white or salmon coloured. 



Hab. near Savannah, Geo. Rev. G. White. 



My cabinet and cabinet of Mr. White. 

 Diam. .1, Length 1.4, Breadth 2.5 inches. 



Shell smooth, elliptical, inflated, very inequilateral, rounded before, subangular behind; 

 substance of the shell thick; beaks somewhat prominent; placed towards the anterior 



