NKW UMOMD.E OF THE UNITED STATES. 87 



Unio verus. pi. 11, fig. 2.31. 



Te-ta l;vvi, subtriangulari, subconipressa, valdO inaequilaterali, postic6 fero rotunda, antiie rotunda ; valvulis 

 crussiusculis, antic^ crassioribus; natibus clevatis; epidermiile fenebro-so-oliva, eradiata, vittata, ad 

 unibones micanti, inferne striata; dentibus cardinalibus parviustulis, conipresso-pyramidatis striatisfjue ; 

 lateralibus subbrevibus, obliquis subrccti.sque ; margarita albil et iridcscentc. 



Shell smooth, subtriaugular, somewhat compressed, very inequilateral, nearly 

 round behind, round before ; valves somewhat thick, thicker beiore ; beaks raised ; 

 epidermis dark olive, without rays, banded, shining on the umbones, striate below; 

 cardinal teeth rather small, compressed, pyramidal and striate ; lateral teeth rather 

 short, oblique and straight; nacre white and iridescent. 

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



Hah. — Cahawba River, Perry Co., Alabama. E. R. Sliowalter, M. 1). 



My cabinet, and cabinets of Dr. Showalter, Dr. Ilartmau and Mr. Anthony. 

 Diam. -G, Length 1. Breadth 12 inches. 



Shell smooth, subtriangular, somewhat compressed, very inequilateral nearly round 

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

 raised; ligament rather short and thin; epidermis dark olive, without rays, with 

 broad bands at the marks of growth, shining towards the beaks, striate at the basal 

 margin, banded along the'marks of growth, which are distant; umbonial slope slightly 

 raised and obtusely angular ; posterior slope narrow, very slightly raised, with indistinct 

 lines on each valve from the beaks to the posterior margin ; cardinal teeth rather 

 small, compressed, pyramidal and striate; lateral teeth rather short, oblique and 

 nearly straight; anterior cicatrices confluent, small and well impressed; posterior 

 cicatrices distinct, moderately large and somewhat impressed ; dorsal cicatrices placed 

 on the plate within the cavity of the beaks ; cavity of the shell shallow and wide ; 

 cavity of the beaks somewhat deep and angular; nacre white and iridescent. 



Remarlcs. — This is a well characterized little species, which in outline is very close 

 to Barnesianus (nobis), but is slightly more triangular. The three specimens before me 

 have their beaks eroded, and therefore the character of the beaks cannot be ascer- 

 tained. This species is not easily confounded with any other. Having broad, dark 

 brown bands, at the marks of growth, it is easily distinguished at once from Barnes- 

 tantcs and from medius, the color of the epidermis also differs; it is a small species, the 

 largest being 1-7 inch wide, and 1-3 inch long. The soft parts were not received, 

 and therefore no comparison of that important portion of the animal can be made. 



UniO PALLIDOF0LVUS. PL 11, fig. 232. 

 Testa, laevi, obliqua, tumida, valde in.icquilaterali, postic6 rotundata, antico rotunda ; valvulis crassis antic^ 

 crassioribus; natibus elevatis, subincurvis; epidermide pallido-fulva, maculata, inferno striata; dentibus 

 cardinalibus parvis, pjrauiidatis striatisquc; lateralibus subcurtis, crassis, subobliquis; niar<'arita ap'oo- 

 tca et iridcscentc. 



