Perkins.] 154 [November 3, 



Pisidium virginicum (Bourg.) Prime, Am. Corbie, p. 61, 

 figs. 61, 62. Cyclas dubia Say, Am. Conch., p. 55, 1816; Gould, 

 Invert. Mass., p. 75, fig. 56. Pisidium abruptum Haldeman, Proc. 

 Acad. Nat. Sc. Phil., Vol. I, p. 53. 



Very rare. 



UNIONLDiE. 



Naia Swainson, 1840. 



Naia complanatus. Unio complanatus Lea, Proc. Acad. Nat. 

 Sc. Phil.; Gould, Invert. Mass., p. 107, figs. 68-70 ; De Kay, Moll. 

 N. Y., p. 188, pi. xxii, fig. 246. Unio purpureus Say, Am. Conch., 

 pp. 50, 135, pi. lxxi, fig. 7, 1816. 



Very common, but usually small and very badly eroded. Animal 

 variable in color, yellow or white; mantle open, thin, white, mottled 

 thickly with yellow flakes, edge plain; gills large and thick, hanging 

 horizontally, straight before, rounded behind, transversely striated 

 with numerous lines, which are connected by fine cross lines, giving 

 to the gill a beautifully tessellated appearance; lower edge darker; 

 inner gill a little larger; foot when extended tongue-shape, half to two 

 thirds as long as the shell; palpi short, broad, rounded at the ends, 

 striated within; siphons very short, barely projecting beyond the 

 shell, broad and flat, fringed with short papillae; ends black, or nearly 

 so, papillae lighter. 



MEASUREMENTS. 



Length of shell 106 mill. Breadth 61 mill. Height 32 mill. 



foot 48 " (contracted). " 13 " 



gills 58 " " 23 " 



palpi 11 " " 5 " 



ventral siphon 30 " " 24 " 



dorsal " 20.6 " " 15 " 



Eurynia, Eafinesque. 



Eurynia nasuta Stimps., Shells of N. E., p. 13 (Agassiz mss.); 

 Morse, Journ. Port. Soc. Nat. Hist., Vol. i, p. 54. Unio nasutus Say, 

 Am. Conch., p. 52, pi. lxxii, fig. 1, 1816; Gould, Invert. Mass., p. 

 109, fig. 71; De Kay, Moll. N. Y., p. 191, pi. xx, fig. 239. 



Collected in West River and Whitneyville Pond by Professor Ver- 

 rill. Not common. 



