776 PLEUROBEMA 
PLEURGBEMA HAGLERI Frierson. 
Shell subelliptical, subinflated, inequilateral; beaks only 
moderately full and high; posterior ridge well developed, slight- 
ly double below, ending at and below the median line in a 
feeble biangulation ; anterior end almost evenly rounded; base 
line curved, quite full just behind the middle; outline of dor- 
sal slope curved, a little more prominent just behind the liga- 
ment than elsewhere; surface with irregular growth lines; epi- 
dermis pale to rather dark reddish-brown, often very faintly 
rayed, scarcely shining ; pseudocardinals triangular, two in the 
left valve, one to three in the right; two laterals in the left 
valve and a scarcely double one in the right; beak cavities 
shallow; muscle scars of moderate size, impressed; nacre 
whitish, purplish or salmon-red, thinner and iridescent behind. 
Length 47, height 34, diam. 20 mm. 
North and Black Warrior Rivers, Alabama. 
Type locality, North River, Tyner, Ala. 
Unio (Pleurobema) hagleri Frierson, Naut., XIII, 1900, p. 
TOO}, ply 1: 
Pleurobema haglert StMPsoN, Syn., 1900, p. 757. 
This species has no strong characters, yet it does not seem 
to be referable to anything else. It is larger, less solid and 
inflated than what I take to be Conrad’s Unio rubellus; it 1s 
lighter colored than that species. It is much lighter colored 
apparently than his U. furvus and does not have the minute, 
crowded wrinkles he mentions as belonging to the latter spe- 
cies. It may be a mere variety of furvus. The swelling just 
behind the middle of the base differentiates it from the Unio 
fassinans of Lea, to which it bears some resemblance. 
PLEUROBEMA RUBELLUM (Conrad). 
Shell rather small, inflated, solid, somewhat triangular or ir- 
regularly elliptical, slightly inequilateral ; heaks full, high; an- 
terior end usually obliquely subtruncate above, slightly cut 
away below, narrowly rounded in the middle; base line 
strongly curved, unusually full in most cases at the middle; 
outline of the dorsal slope curved; posterior ridge well devel- 
