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, th€ various forms of the nebnlosa 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 Ligumia 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 tceniatits 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 

 intcrrnptus. 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 interruptns, in other respects 

 it agrees quite as well as tceniata. It would seem to us that 

 it is quite as possible that Rafinesqvie had one of these or some 

 allied species before him as that he had brevidens. 



"The Rafinesque-Poulson specimen of interruptns is a female 

 brevidens, very solid, diameter nearly one-half the length. 



