4-2 NKW UNIONID.^*: OF THE 



subconcentrically undulate at tlio tips; epidermis dark olive, shining, obsoletely 

 rayed; cardinal teeth small, erect and crenulate; lateral teeth long, lamellar and 

 somewhat curved; nacre bluish and very iridescent. 

 Proo. Acad. Nat. Sci. 1857, p. 84. 



Hah. — Dewitt County, Texas. W. Newcomb, M. D. 



My cabinet and cabinet of Dr. Newcomb. 

 Diam. -5, Length -8, Breadth 1-4 inch. 



Shell small, elliptical, subcompressed, very inequilateral, subangular behind and 

 rounded before ; substance of the shell rather thru, thicker before ; beaks slightly 

 prominent, very beautifully and subconcentrically undulate at the tips; ligament 

 small, thin and yellowish brown ; epidermis dark olive, shining, obsoletely rayed, with 

 distant marks of growth ; umbonial slope slightly raised and obtusely angular ; pos- 

 terior slope very slightly raised, with two dark lines on each valve from the beaks to 

 the posterior margin ; cardinal teeth small, erect and crenulate ; lateral teeth long, 

 lamellar and somewhat curved ; anterior cicatrices distinct, small and well impressed ; 

 posterior cicatrices confluent and slightly impressed ; dorsal cicatrices placed across 

 the cavity of the beaks ; cavity of the shell somewhat deep and Avide ; cavity of 

 the beaks shallow and obtusely angular ; nacre bluish and very iridescent. 



Remarks. — Several specimens were sent to me by Dr, Newcomb, of Albany, N. Y. 

 It is a small species near to parvus, Bar., but it is more oblique, more compressed, 

 has a shining epidermis and has more and smaller undulations at the tips. It is very 

 much like U. Bairclianus (nobis), herein described, and may prove to be the male of 

 that species. 



Unio quadrans. pi. 61, fig. 185. 



Tftsta Isevi, quadrata, valde ventricosa, subsequilaterali, postic^ obtuse angulata, antice .subtruncata ; valvu- 

 lis crassis, antic6 paulisper crassioribus ; natibus elevatis, tumidis; epidermidc tenebroso-fusca , 

 eradiata^ trani3vers^ striata ; dentibus cardinalibus m'agnis, valde compressis, striatis crenulatisque ; later- 

 alibus longis, crassis curvisque ; margarita alba et iridescente. 



Shell smooth, quadrate, very much inflated, nearly equilateral, obtusely angular 

 behind and subtruncate before ; valves thick, somewhat thicker before ; beaks raised 

 and swollen; epidermis dark brown, without rays, transversely striate; cardinal 

 teeth large, very much compressed, striate and crenulate ; lateral teeth long, thick 

 and curved ; nacre white and iridescent. 

 Proc. Acad. Nat. Sci. 1860, p. .S06. 



ifofe.— Texas. C. M. Wheatley. 



Cabinet of Mr. Wheatley. 

 Diam. 2, Length 2-8, Breadth 3-6 inches. 



Shell smooth, quadrate, very much inflated, nearly equilateral, obtusely angular 

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



