MURIDA—SIGMODONTES—HESPEROMYS AUREOLUS. 93 
4703, from the Southern States, probably Georgia, the under parts are not 
white at all, nor even whitish, but cinnamon, only a little paler than the sides. 
No. 981 has quite a black stripe along the back. No. 2964, from Illinois, is 
interesting in several respects. In the first place, the feet are remarkably 
small, less than in any Hesperomys we have seen, except michiganensis; and 
in some other respects, especially ‘‘buccis flavis”, it corresponds better with 
Audubon and Bachman’s description of michiganencis than the specimens we 
have referred to that species do. The under parts, moreover, are white. The 
general color of the upper parts, while showing unmistakable traces of the 
peculiar orange shade of aureolus, are much watered with a darker hue. This 
is another case of darker hue in Illinois rodents than elsewhere; for the 
Arvicola riparius, Pitymys pinetorum, and Hesperomys leucopus, all show this 
peculiarity. A Saint Louis, Mo, skin might be referable to this species with 
a shade of doubt, were it not accompanied by a little suckling one, possibly 
its offspring, which settles the case, and at the same time confirms the valid- 
ity of the species in a very satisfactory way. This little creature is of the 
same bright orange-cinnamon as the adults, while, as is well known, the young 
of /eucopus are, for some months, of a dark ashy-gray. 
I only venture to include in this series a specimen (No. 548) from the 
Schuylkill River, Pa., with grave doubt. The animal appears to have been 
skinned out of alcohul, and the yellowish tinge of the under parts may be 
due to discoloration. In other respects, it is more like /eucopus than aureolns, 
haying dusky ears, sharp line of demarkation along the sides, &e. 
Doubtless, after all, there are some who would prefer to consider H. 
auroleus as a ‘permanent variety” of /eucopus, but they need to be reminded 
that such course would remain simply a peéitio principii until they explain 
the difference between a ‘permanent variety” and a “species”. 
The figure and description of Arvicola nuttalli, Warvan, agree very well 
with the present species; but, as they represent a bright-colored leucopus 
quite as well, and contain nothing positively distinctive, I agree with Mr. 
Allen that it is not necessary to supersede the well-known and very expressive 
name aureolus. 
