80 RAFINESQUE’S 
105 Sp. <Alasmodon viridis (L. viridis disc. 1820.) Shell thin 
swelled, subelliptical, quadrulated, posterior slope slanting truncate 
without ribs: outside greenish, nearly smooth, inside bluish, with 
flexuose wrinkles. Length 1-2, diameter 1-3, axis 1-3 of the 
breadth. 
Var. I. Chloris. Bright green. 
Var. II. Radiata. Olivaceous with green rays. 
Var. III. Fuscata. Brownish. 
In the Ohio and other streams. So much like Unio viridis out- 
side as to be easily mistaken for it. Tooth small bilobe crenate, 
angular projection sharp with a wrinkle or furrow. One or two 
inches broad. 
. 5 N. G. AMBLAMODON. 
106 Sp. Alasmodon hians (Amblasmodon hians, 1823.) Shell 
thick; much swelled, elliptical, subobliqual and gaping, margin flex- 
uolate, posterior slope with broad ribs. Outside rugose and yellow-~ 
ish brown, inside even pale incarnate. Length 7-20, diameter 2-5, 
axis 1-4 of length. 
River Tennessee, fine rare shell, 5 inches broad. Hinge quite 
peculiar, cardinal tooth not lobed, large subcrenate, large oblique 
knob on the projection decurrent, tavisted and curved behind. 
6. N. G. DECURAMBIS. 
107 Sp. Alasm. scriptum (Decurambis literata dise. 1822.) 
Shell rather thin, subelliptical, very much swelled, truncate behind, 
nearly flat with transverse furrows and ribs, subsinuate beneath. 
Outside smooth greenish with blackish spots like capztal letters !— 
inside bluish. Nearly equilateral, apex ardate. Length and 
diameter one half, axis 5-12 of the length. 
In Green river. Wonderful shell, exceedingly rare and strange, 
outside form of a Truncilla, 2 or 3 inches broad. Tooth flexuose 
trilobe compressed, decurrence befid before. Certainly a peculiar 
genus. ; 
108 Sp. Alasm. atropurpureum (Decurambis ditto. disc. 1823.) 
Shell rather thin, elliptical, hardly swelled, smooth and not truncate 
behind, subsinuate beneath: outside rugose, blackish purple, quite 
inequilateral, apex hardly cordate. Length one half, diameter and 
axis one third of the breadth. 
In the river Cumberland, very rare, 3 inches broad. Tooth flexuose 
subtrilobe, hardly prominent. Very distinct from the last, although 
a true Decurambis. 
