172 7 T. A. Conrad on a new species of Unio. 
I have stated that the cryolite has been employed here in Ber- 
lin under the name of mineral soda for the preparation of eaustic 
adapted to the manufacture of soap. In fact the pulverized oF 
olite is decomposed entirely if boiled in this condition with cau 
tic lime and water. The fluorid of calcium thus generated ae 
tains no aluminous earth, this being entirely dissolved in the hy- 
drate of soda, which again is free from fluorine or shows but a 
Arr. XXI.—On a new Species of Unio; by T. A. Conran. 
Unio diversus. 
Trapezoidal, ventricose, inflated posteriorly, substance of shell 
generally thin, thicker anteriorly and 
thickest or somewhat callous towards 
the base ; valves contracted from beak 
a to base, posterior margin obliquely 
ae truncated, rectilinear, ligament and 
margins parallel; posterior ex- 
profound; epidermis yellowish oliv 
clouded with dark brown; rays obsolete or wanting; within 
greenish or wax-colored ; dirty white towards the anterior base; 
cardinal tooth in right valve compressed, oblique, crested, promi- 
nent; in the opposite valve 3-lobed, the posterior lobe opposite 
the acne middle lobe small or obsolete ; lateral teeth straight, 
Tahsbits Shoal Creek, N. Alabama. Prof. Thomas P. Hatch. 
Remarkable for its resemblance to U. heterodo on, Lea, and like 
i wing the double lateral tooth in the right valve. 
tooth of the left valve has the same extended char- 
heterodon, and 1 think these two species will be 
tute a distinct subgenus when the animals have 
Perhaps it may interest conchologists to 
pecies inhabits the Schuylkill river, at Phoenix- 
degree three specimens in a very limited time ; and 
procured a number of living specimens in the 
opposite Trenton, just below the falls. a4 
