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PLEUROBEMA 
Group of Pleurobema bulbosum. 
Sheil elongate oval, solid, inflated, with a high posterior 
ridge, ending in a point behind, above which it is feebly wrin- 
kled; beaks full, sculpture not seen; epidermis smooth, dark, 
rayless; hinge strong; pseudocardinals heavy, torn, sometimes 
a small third one in the left valve; laterals heavy, club-shaped, 
granulate, two in the left valve and one and a small secondary 
lateral in the right. Animal unknown. 
PI#ZUROLEMA BULBOSUM (Lea). 
Shell irregularly ovate or subelliptical, inequilateral, moder- 
ately solid; beaks high and full; posterior ridge high, suban- 
gular above, narrowly rounded below, ending in a point on 
the median line; dorsal slope somewhat truncated and wrin- 
kled; surface with irregular growth lines; epidermis black, 
subshining ; pseudocardinals small, rough, two in the left valve 
and one to three in the right ; laterals two in the left valve and 
a decidedly double one in the right; beak cavities shallow ; 
muscle scars small; nacre whitish, purplish or salmon-colored. 
Length 47, height, 31, diam. 20 mm. 
Length 45, height 29, diam. 20 mm. 
Ocmulgee and Flint rivers, Georgia. 
Type locality, Flint River, Macon, Ga. 
Unio bulbosus Lea, Pr Ac N. Sei) Phila 1X) 1857.0p. 2172. 
jk Ac NS Ser Phula.. 1V5 1850> p. roi. placa nesace Ons. 
Wil, 1850, De 0. ph xxi noms 
Margaron (Unio) buibosus Les, Syn., 1870, p. 40. 
Pleurobema bulbosa SIMPSON, Syn., 1900, p. 759. 
This group is quite different from any other of the genus 
Pleurobema and | am not positive as to its relationships, though 
the general form, small muscle scars and double lateral of the 
right valve incline me to place it here. The truncation of the 
post-dorsal slope, and its wrinkles, together with the black epi- 
dermis are peculiar characters. 
PIEUROREMA HARPERI (B. H. WricH’r). 
Shell oval, subinflated, subsolid, inequilateral ; beaks full and 
high; posterior ridge angled above, double below, ending in a 
biangulation at and below the median line; anterior end some- 
