Occasional Papers of the Museum of Zoology 67 
occurrence of brevidens in the Ohio. It is not given in any 
of the Ohio lists that we have seen. Brevidens is a character- 
istic species of the Tennessee system. Like some other Ten- 
nessee species, by stream transference in the head-waters, it 
has got into the Cumberland River, but not out into the Ohio. 
We know practically nothing of the fauna of the Kentucky. 
We have no records of this species having been found there. 
On the other hand, the various forms of the nebulosa group 
are generally distributed in the Ohio and its southern tribu- 
taries. It seems very strange that Rafinesque seems never to 
have collected any species of that group. At least none have 
been identified among his species. 
An “ovate-elliptical shell, not thick, and little swollen, with 
reddish-brown epidermis and interrupted rays and white 
nacre,” may be very well applied also to forms of Ligumua of 
the nebulosa-iris group. 
In this connection attention should also be called to the 
possibility that Rafinesque’s shell may have been a specimen 
of teniatus Con. A specimen of nearly the same size has 
exactly the same proportions as those given by Rafinesque 
for his shell. In all other respects, except perhaps color, 
including the character of the lateral teeth, it agrees with 
interruptus. While this species does not occur in the Ohio, 
it is found in the Cumberland and is quite likely to be found 
in the Kentucky as brevidens. 
Punctata Lea would also apply. Except that it is usually 
not so high proportionately as mterruptus, in other respects 
it agrees quite as well as teniata. It would seem to us that 
it is quite as possible that Rafinesque had one of these or some 
allied species before him as that he had brevidens. 
“The Rafinesque-Poulson specimen of interruptus is a female 
brevidens, very solid, diameter nearly one-half the length, 
