86 THE NAUTILUS. 
pale orange or orange-brown. The eggs and placentae are 
whitish, cream color, pale yellow, but in most cases of a pecul- 
iar and characteristic pale orange, and also the gonads of the 
female often have the same color. These colors agree with 
those of P. clava, but incline more frequently to the pale orange 
type. It should be remarked, however, that all specimens from 
Little River, Blount Co., Tenn. (about a dozen) represent a 
peculiar color variety. The structure of the soft parts is en- 
tirely normal, but the color is of the orange type, and the pla- 
centae are bright red (in over half a dozen gravid females). 
The shells of these specimens do not at all differ from those of 
the form argentewm as found in Virginia, except that the color 
markings of the epidermis are absent, and that the latter is 
comparatively dark (brown to black-brown). However, all of 
my specimens of this form are rather large. One of my females 
from Chickamauga Creek had pink placentae, the others had 
them cream color, as is normal. 
Of the typical P. oviforme (form of the rivers of medium size), 
gravid females have been found on May 11, 18, ’18; May 20, 25, 
14; July 5, 7, 9, 10, 18, 718. Glochidia are at hand from 
July 5. 
The anatomy is exactly like that of P. oviforme argenteum, as 
described above, and the glochidia have the same shape and 
size (0.16 mm. ). 
Color of the soft parts whitish, inclining on foot and mantle 
often to yellowish-brown or pale orange. Ova and placentae 
white, more rarely cream color or pale orange. Thus, in color, 
this form more closely resembles P. clava. 
Of the swollen type, P. oviforme holstonense, I have found only 
few specimens. No gravid females have been secured, but 
sterile females and males. The anatomy is exactly as in typi- 
ical oviforme. 
Jote. Lexingtonia dolabelloides conradi, chiefly in young speci- 
mens, often resembles the typical P. oviforme in the shell. But 
in the color of the soft parts they are quite distinct, and the in- 
tensely orange tints seen in the former have never been observed 
in the latter. Gravid females of P. oviforme are recognized also 
by the light-colored placentae, which are not quite so solid a 
