43 
UNIO ALTI LIS. 
Plate II. — Fig. 1 . 
DESCRIPTION. 
Shell suboval, thin, inflated; beaks slightly promi- 
nent and much decorticated; posterior margin suban- 
gulated; umbonial slope rounded, behind which is an 
obscure rib declining from the beaks to the posterior 
extremity; base arcuated; epidermis blackish, rugose, 
olivaceous over the umbones and rayed; and with 
numerous short vermicular lines on the posterior 
slope; cardinal teeth subpyramidal, erect; lateral 
teeth distant; a profound elongated muscular impres- 
sion on the callus; nacre whitish and iridescent. 
OBSERVATIONS. 
Inhabits the Alabama river, near Claiborne, and is 
rather rare. Young specimens resemble in outline 
the U. mnltiradiatus, Lea. Old shells have the epi- 
dermis almost black. 
UNIO PEROVALIS. 
Plate II. — Fig. 
DESCRIPTION. 
Shell oval, moderately thick, inflated; beaks promi- 
