THE NAUTILUS. 3 
the (height of the) whorl, and by the wanting constriction, especially 
in the columellar wall, not to speak of the size and shape of the whole 
shell. The lamellse also show some marked differences, such as the 
presence of a high basal, the shorter columellar not reaching the 
base, but with relatively larger horizontal part, the bifurcation of the 
parietal and the presence of a supra-palatal, the last just as it is in 
P. armifera. 
It must be added here that the specimen first obtained from 
Minnesota in several respects differs from those found in Illinois and 
Iowa, which I consider as typical ; by its size which is $+ smaller, by 
the basal lamella developed in a peculiar way, being rather longer 
at the truncated top than at its foot, and by the stronger, thicker 
palatal lamelle. Yet, as there was only one specimen, it was liable 
to be an individual peculiarity—even then of interest. Should, 
however, more specimens be found with the same configuration, they 
would represent a distinct and well characterized variety ; possibly 
it is a peculiar northern form. 
New Philadelphia, Ohio, June, 1889. 
ON MR. PILSBRY’S CRITICS UPON SOME AMERICAN SHELLS. 
BY C. EVAN C EY. 
In the 9th No. of the Conchologists’ Exchange, Vol. II, 1888, p. 
113, Mr. H. A. Pilsbry wrote: “On Lyogyrus, Gill, and other 
American shells,” in which several subgeneric and specific names 
proposed by European scientists for N. American shells, particularly 
by Dr. Westerlund and myself are sharply criticised. Of course 
criticism is good whenever errors generally diffused are to be 
destroyed, and when not inconsiderate. I intended, at first, to write 
about this subject in “Le Naturaliste,” where “some of Mr. Crosse’s 
genera are so rudely handled,” but I at length determined to insert 
my article in the same paper as that in which Mr. Pilsbry published 
his own note, in order to be read by the same naturalists. 
It will be remarked at first, that before speaking about the new 
species proposed by such a man as Dr. Westerlund, an eminent 
conchologist, and certainly, together with Dr. W. H. Dall, the one 
who is the best acquainted with the conchological fauna of the Arctic 
countries, it would be well to compare either his shells with authen- 
tic specimens of those formerly described, or his very accurate 
