270 ANNALS OF THE CARNEGIE MUSEUM. 
Elliptio jayensis (Lea). 
Five males and twelve females (all sterile) from Lake Monroe, 
Sanford, Orange Co., Florida, collected by O. T. Cruikshank, in 
April, 1907. 
The soft parts are of the usual structure, and agree in every particular 
with those of E. complanatus. Anal and supra-anal separated by a 
mantle-connection, which is slightly longer than in the more primitive 
forms, but still considerably shorter than the anal. Anal with rather 
well developed papillz, which are almost as large as the papillz of the 
_ branchial opening. Posterior margins of palpi connected at base only. 
Inner Jamina of inner gill free, except at anterior end. Only the outer 
gills are marsupial. 
The beak-sculpture of this species is nct quite of the normal Elliptio- 
type, in that in the case of the later bars a sinuation is seen in front 
of the posterior angle. This sinuation is variable, and never assumes 
the shape of a distinct, reéntering angle, and thus the beak-sculpture 
cannot be called double-looped. 
There are over one hundred shells (without the soft parts) at hand, 
many of which might as well be called E. buckleyi (Lea). All these 
shells undoubtedly are the same species, and were collected together. 
The old ones most resemble buckleyi (see: Simpson, 1892, pl. 58, 
figs. 6 and 7, and pl. 50, fig. 1), while those of medium size and the 
young ones are jayensis (Simpson, zbid., pl. 61, fig. 4). It is remarkable 
that there are no young buckley in the lot, while there are dozens of 
jayensis. JT am very much inclined to regard buckleyi as being only 
the older adult form of jayensis. 
Elliptio productus (Conrad). 
Nine specimens have been investigated, males and sterile females, 
from the Potomac drainage in southern Pennsylvania and Maryland. 
The soft parts agree in all essential respects with those of E. com- 
planatus. Conforming to the shape of the shell, the gills are extremely 
long and narrow. Branchial, anal, and supra-anal as in complanatus; 
anal and supra-anal separation slightly longer than usual; anal with 
the same distinct papilla. Structure of palpi and gills the same. 
No gravid females have been found. 
Color of soft parts like that of complanatus. 
Beak sculpture practically identical, and there is no doubt that this 
species is an offshoot of the complanatus-stock. 
