262 Mr. Barnes on the Genera Unio and Alasmodonia. 
Unio purpurata? = M. Lamarck. 
_ Inhabits Fox River. Mr. Schoolcraft. 
Wisconsan. Capt. Douglass. 
Cabinets of the Lyceum and Dr. Mitchill. 
y Collection. 
Diam. 1.7--2.1 Length 2.5—2.7 Breadth 5.8—6.4 
Shell very long oval; anterior side somewhat pointed, 
posterior side short, rounded, obtuse ; beaks depressed ; lig- 
ament elevated above the beaks ; basal margin slightly com- 
pressed, shortened, or, in old specimens, arcuated; in young 
rounded; epidermis blackish brown, with fine interrupted 
wrinkles placed in ee ee rows, having somewhat the 
appearance of striz. Young specimens are rayed with yel- 
lowish olive, and have the epidermis smooth and glabrous. 
Naker purple of different shades according to the age or per- 
fection of the specimen, sometimes tinged with irregular 
spots of greenish, particularly under the beaks, with a row 
of small muscular impressions in the cavity. 
Remarks.—This shell is probably the Unio purpurata of 
M. Lamarck. (See introductory remarks.) We have every 
size from the breadth of one inch, to six inches and four 
ines. 
Variety (a.) Shell on the inside striated longitudinally. 
Naker red-purple, very splendid. 
Variety (b.) Naker whitish green on the margin, and pur- 
ple in the centre. An uncommonly beautiful shell, tinged 
ath copper ? 
é My Collection. 
14. unio GiB 2 gk? aN 
ipposus. Fig. 12 b. outside. 
Shell elongated transversely, thick, gibbous ; lateral 
tooth very thick, incurved, inside purple. 
Inhabits Wisconsan,, Mr. Schoolcraft. 
ly collection. Lyceum’s Cabinet. 
Mr. Say’s Collection. Philadelphia. 
Diam. .75—1.3 “Length 1.15—1.9 Breadth 2.4—4.0 
_Shell much elongated transversely, thick and heavy, T- 
pidly narrowed and rostrate before, narrow and rounded be- 
