DESCRIPTION OF FIFTY-TWO SPECIES OF XJNIONIDJil. 29 



My cabinet and cabinets of Dr. Lewis and Mr. Wheatley. 

 Diam. -7, Length 1-2, Breadth 1'4 inch. 



Shell smooth, triangular, somewhat inflated, flattened at the sides, obtusely 

 angular behind and rounded before; substance of the shell somewhat thick, thicker 

 before; beaks somewhat prominent, incurved, minutely undulate at the tip ; liga- 

 ment short, thick and light brown ; epidermis yellowish, with interrupted green 

 rays over about half of the disk, with rather close marks of growth; umbonial slope 

 obtusely angular ; posterior slope cordate, with an indistinct impressed line from 

 the beaks to the margin ; cardinal teeth small and corrugate ; lamellar teeth short, 

 rather thick, corrugate and somewhat curved ; anterior cicatrices distinct, small and 

 deeply impressed ; posterior cicatrices distinct and well impressed ; dorsal cicatrices 

 within the cavity of the beaks ; cavity of the shell shallow ; cavity of the beaks 

 somewhat deep and angular ; nacre silver white and iridescent. 



RemarJcs. — This is another of Miss Law's species from Clinch Kiver, and belongs 

 to that group of triangular smooth Uniones of which obUquus, Lam. may be con- 

 sidered the type. It is very nearly of the same outline, but is more compressed, 

 is a thinner shell and has not the beaks so much elevated. It also has some resem- 

 blance to ruhiginosus (nobis), but is not rubiginose nor quite so angular. In outline 

 very near to Tuscumhiensis, but more inflated. It may easily be distinguished from 

 tumescens (nobis), an allied species, by the latter being more inflated and being of 

 a darker color. The specimen from North Alabama sent to me many years since 

 by Mr. White, is larger than the four from Miss Law, and is higher in the beaks, 

 is more inflated and has more distant marks of growth. Indeed, Mr. White's 

 specimen may prove, when we have more to examine, to be really distinct. 



Unio pauciplicatus. pi. 9, fig. 26. 



Testa plicata, subrotunda, ventricosa, valde insequilaterali, postice carinata, antice rotundata; valvulis 

 crassis, antice crassioribus ; natibus prominentibus, tumidis, recurvatis, ad apices minute undu- 

 latis ; epidermide rufo-fusca, eradiata ; deatibus cardinalibus crassis, elevatis, sulcatis erenula- 

 tisque ; lateralibus longis, lamellatis, corrugatis subcurvisque ; margarita argentea et valde irid- 

 escente. 



Shell plicate, subrotund, very much inflated, very inequilateral, carinate behind 

 and rounded before ; valves thick, thicker before ; beaks prominent, swollen, re- 

 curved and minutely undulate at the tips; epidermis reddish-brown, without rays; 

 cardinal teeth thick, raised, sulcate and crenulate ; lateral teeth long, lamellar, 

 corrugate and slightly curved; nacre silver white and very iridescent. 

 Proc. Acad. Nat. Sci., 1872, p. 156. 



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