THE NAUTILUS. 79 



Museum of Natural History in New York City, I 'have had the 

 opportunity of examining an author's example of this rare species. 

 This specimen, though not quite as large as the type, agrees with 

 the description in all other particulars. The locality is given as 

 Kentucky and there is but little doubt that it is one of the original 

 lot. 



It is a remarkably strong, heavy shell, as compared 'with the other 

 eastern species, and differs from them all in its size, greater eleva- 

 tion and the convex outline of the posterior slope. The marginal 

 outline is broadly oval, the greatest width being behind the centre 

 and immediately under the apex. The apex is quite acute and 

 turned toward the right. The apical striae are strong and close to- 

 gether at the apex, but rapidly diminishing in size, and the strong, 

 irregular lines of growth on the outer half of the circumference are 

 scarcely more than rippled by the radial lines. The apical portion 

 of this specimen was quite heavily encrusted with lime, which I did 

 not attempt to remove, and which covered up any indications of the 

 rosy color mentioned by Anthony in his description. The irregular 

 shape of this specimen is no doubt an individual peculiarity, caused 

 by a change in the line of growth after a period of rest, possibly a 

 change in the object on which the shell rested. Down to the line 

 where the new growth began, the outlines are quite regular, but be- 

 low it, there is first a decided constriction, rather more marked in 

 the posterior and left slopes, and then a rapid expansion all around 

 the circumference. Similar instances have already been described 

 as occurring in A. parctllelus. The dimensions of this specimen are : 

 Length 5.75, breadth 4.5, alt. 3 mm. 



Accompanying this shell were two smaller ones of evidently a dif- 

 ferent species, apparently the same as that found by Hinkley in the 

 Ohio River, and which will be more fully described in connection 

 with that form. In Mr. Hinkley's collection is a single specimen ot 

 the genuine elatior, which was collected by him in a creek near Flor- 

 ence, Ala. The apex is badly eroded, but the rosy tinge is very 

 evident. Its dimensions are: Length 5, breadth 4.8, alt. 2.5 mm. 



The outline is entirely regular without any trace of the constric- 

 tion shown in the Anthonyan specimen. 



VII. Ancylus avails Morse (1864). 



I have not been "able to get any information in regard to this 



