2G8 DESCRIPTION OF NEW 



Remarks. — Among the many shells from Georgia which I owe to the kindness of Major 

 Le Conte, was a single specimen of this species. It is allied to U. Lecontianus, (Nobis,) 

 and is like it in outline; but it is more compressed, higher in the carina, and much more 

 striate and rough on the exterior ; it is also a thinner shell. The posterior margin of this 

 specimen is also slightly emarginate. The tips of the beaks are not perfect, but they are 

 enough so in this specimen, to show that the undulations are more numerous than usual 

 and very beautiful. The upper portion of the double lateral tooth is very small in this 

 specimen. 



Unio Moussonianus. PI. XVIII. Fig. 22. 



Testa Isevi, ellipticd, subconvexd, subinequilaterali, postici angulatd ; valvulis percrassis ; natibus promi- 

 nentibus, crassis ; epidermide castaneo-fuscd ; dentibus cardinalibiis magnis, sitbeompressis ; lateralibus 



longis, crassis subcurvatus ; margaritd argented et iridescente. 



Shell smooth, elliptical, subconvex, subinequilatcral, angular before; valves very thick; beaks prominent and 

 thick; epidermis chestnut-brown; cardinal teeth large, rather compressed ; lateral teeth long, thick, somewhat 

 curved ; nacre silvery white and iridescent. 



Hab. Georgia, J. P. Barratt, M. D. 



My cabinet and cabinet of Dr. Barratt. 

 Diam. 1.1, Length 1.8, Breadth 2.8 inches. 



Shell smooth, elliptical, subconvex, somewhat inequilateral, angular behind and rounded 

 before ; substance of the shell very thick, rather thinner behind ; beaks prominent and 

 thick; ligament rather long and thick; epidermis chestnut-brown, marks of growth distant 

 and rather distinct; umbonial slope obtusely angular; cardinal teeth large, rather compressed, 

 double in the left and single in the right valve; lateral teeth long, thick, laminate, thick- 

 ened towards the posterior end and slightly arched; anterior cicatrices distinct; posterior 

 cicatrices distinct ; dorsal cicatrices placed on the under side of the plate, near to the 

 edge ; palleal cicatrix impressed ; cavity of the shell not very deep ; cavity of the beaks 

 rather shallow and angular; nacre silvery white and iridescent. 



Remarks. — The outline and general appearance of this species reminds one of U. dclo- 

 dontus, Lam. It is, however, a thicker shell and has thicker teeth. But three specimens 

 were received by me. One of them is slightly tinged with salmon colour in the cavity 

 of the beaks, and others may be found very likely more deeply coloured. 



I dedicate this species to Prof. A. Mousson, of Zurich, the author of " The Land and 

 Fresh Water Shells of Java." 



Unio nigerrimus. PI. XVIII. Fig. 23. 



Testa ln;vi, ellipticd, subconvexd,insequilaterali,postice subrolundatd; valvulis subtenuibus; natibus parvis, 

 prominulis, ad apices undulatis; epidermide nigra, nitidd, striata} dentibus cardinalihus subeompressis, 

 obliquis, acuminalis, en nulatis; lateralibus longis, lamellatis subcurvisque; margaritd a/ba et valde iridescente. 



Shell smooth, elliptical, rather convex, inequilateral, rounded behind; valves rather thin; beaks small, slightly 

 prominent, undulated at the tip ; epidermis black, shining, striate ; cardinal teeth rather compressed, oblique, 

 acuminate, crenulate ; lateral teeth long, lamellar and somewhat curved ; nacre white and very iridescent. 



