780 PLEUROBEMA 
subangular or narrowly rounded, ending at or below the me- 
dian line in a blunt point; anterior end evenly rounded; base 
line curved, fuller behind the middle; outline of dorsal slope 
curved, raised to an angle behind the ligament; surface nearly 
smooth; epidermis greenish-yellow, clouded or irregularly 
marked with broad bands of rich green and these are broken 
by faint, light rays; rest marks often distinct ; pseudocardinals 
two in the left valve and three in the right; laterals two in the 
left valve and a somewhat double one in the right; muscle scars 
small; beak cavities shallow; nacre bluish-white, thinner and 
iridescent behind. 
-Length 37, height 23, diam. 18 mm. 
Alabama River system. 
Type locality, Connasauga and Etowah Rivers, Ga. 
Umo johannis Lea, Pr. Ac. N? Scr Phila, TEL 1Ss5o.ap= 1705 
jl Ac: NaScu ‘Phila, 1V.1860ep. 340. pla hve iS. foe sO Ds 
VIII, 1860, p. 25, pl. Lv, fig. 168. 
Margaron (Unio) johannis Lea, Syn., 1870, p. 41. 
Pleurobema johannis StmMpson, Syn., 1900, p. 759. 
Shorter and solider than P. flavidulum and having a very 
different color pattern from it or P. hanleyanum. ‘The largest 
specimen I have seen is covered all over with what appears 
like low blisters of the epidermis, but this character is not 
present in other shells I have seen. 
PLEUROBEMA HANLEYANUM (Lea). 
Shell irregularly elliptical, subinflated to inflated, inequilat- 
eral, rather solid; beaks full and high; posterior ridge low, 
narrowly rounded, ending in a blunt point about at the median 
line; in front of the ridge the disk is decidedly inflated; ante- 
rior end rounded; base curved, full behind the middle; outline 
of the dorsal slope curved, most elevated behind the ligament ; 
epidermis brownish or greenish-brown, somewhat cloth-like, 
showing the dark rest marks plainly ; pseudocardinals triangu- 
lar, two in the left valve and one to three in the right; two 
short laterals in the left valve and a more or less double one 
