§2 THE NAUTILUS. 
was of nearly the same shape in both species, but that of 
‘* biseriatus’’ was dark-colored, from horn in the upper part to 
black at the cutting edge, while the jaw of caroliniensis is of a 
yellowish or reddish horn. The details of the surface must be 
compared with more material. The radula, with its anterior 
(older) end torn off, had 141 (+ . . .) rows of 45 + C + 45 
teeth of rather the same shape as those of caroliniensis ; only the 
mesodonts of the outer laterals (about 1déth—25th) seemed 
larger and longer; one of the caroliniensis had 210 rows of 
54 + C + 54 teeth. 
As Mr. T. D. A. Cockerell suggested, some of the so-called 
color variations of P. caroliniensis may prove to be distinct 
species. This, and their interrelations, and those of variation, 
or varieties, should be carefully ascertained and also their dis- 
tribution. It may be mentioned, in this connection, that P. 
wetherbyi W. G. Binney, originally known from Kentucky, has 
also been found in northern Michigan, as stated by B. Walker. 
Scientifically it may not be justified to publish these rudi- 
mentary notes. But there is another reason for doing so. The 
season is already well advanced. These interesting slugs have 
been badly neglected, and our knowledge of them is still far 
from satisfactory. Besides, they are getting more and more 
scarce in consequence of deforestation of the land, and will dis- 
appear in many sections before long, and faster than most other 
snails. Therefore, every conchologist should pay special atten- 
tion to anything in this line that can be found. And, to men- 
tion it again, by the way, the term ‘‘shells’’ is not the proper 
one to be used in books and catalogues; we should say mol- 
lusks! 
With respect to the generic name, I agree with W. G. Binney 
that the forms and species known should be ranged under one 
genus, whether their jaws be ribbed or not, if there are no other 
more significant differences. The jaw of the Chippewa slug 
seems to be really intermediate between the ‘‘smooth’’ and 
ribbed forms. W. G. Binney rejects the name Philomycus, be- 
cause Rafinesque did not correctly describe this genus under 
that name. There is hardly a conchologist who doubts now 
but that Rafinesque really understood the slugs under consider- 
