CHIEFLY OF THE UNITED STATES. . 49 



cavity of the beaks rather shallow and subangular; nacre purplish and very 

 iridescent. 



• Remarlcs. — This species is very much the size and form of some varieties oi parvus, 

 Bar., and of course somewhat like germanus (nobis,) but it differs from both entirely 

 in the undulations of the beaks. Both of these have them subconcentric, while in 

 granulatus the beaks are covered with wave-like granulations, which are remarkable, 

 and extend for some distance down the sides, being different in this character from 

 any species I know in this country, but which closely resemble those in Napeanensis, 

 Con., from Australia. In outline it i*more elliptical than that shell, and it differs 

 in the color of the nacre being purple, and in the epidermis not being black, also in 

 being comparatively a diminutive species. In the character of the undulations it is 

 very closely allied, but in our species they are closer and smaller, and extend further 

 in proportion to the sizes of the two shells. The undulations, in the specimen before 

 me, are visible in the cavity of the beaks. It is to be regretted that I have only a 

 single specimen, and that without the soft parts to compare with parvus and germa- 

 nus. The specimen before me has a single dark line of growth more than half-way 

 down, and may not be full grown. This specimen is disposed to be sulcate on the 

 anterior portion of the disk, and this may possibly be a permanent character. 



Unio germanus. pi. 19, fig. 54. 



Testa laevi, elliptica, subinflata, inajquilaterali, postice subbiangulata, antice rotunda ; valvulis crassiuscu- 

 lis, antice crassioribus ; natibus subprominentibus, ad apices concentrice rugoso-undulatis ; epider- 

 mide tenebroso-fusca, eradiata, transverse striata; dentibus cardinalibus parvis, erectis, compressis, 

 crenulatis, acumlnatis ; lateralibus tenuibus subcurvisque; niargarita purpurescente et valde 

 iridescente. 



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

 round before ; valves somewhat thick, thicker before ; beaks rather prominent, with 

 rough concentric undulations at the tips; epidermis dark brown, without rays, 

 transversely striate ; cardinal teeth small, erect, compressed, crenulate and pointed ; 

 lateral teeth thin and somewhat curved ; nacre purplish and very iridescent. 

 Proc. Acad. Nat. Sci., 1861, p. 40. 



Hob. — Coosa River, Alabama, E. R. Showalter, M. D. 



My cabinet and cabinet of Dr. Showalter. 

 Diam. -55, Length -82, Breadth 1-40 inches. 



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

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

 prominent, concentrically and rugosely undulate at the tips ; ligament short, thin 

 and lightish brown ; epidermis dark brown, without rays, transversely striate? 



13 



