No.411.] REVIEWS OF RECENT LITERATURE. 223 
vague localities. If he has some *' inside history " to fall back upon, 
it is only fair that the secret should be made public. 
It may be said further, in the way of gentle criticism, that it is 
hardly fair wholly to ignore such knotty points as the allocation of a 
few names which he omits, since they form part of the literature 
of the subject, as, for example, ypudeus ochrogaster Wagner, Arvi- 
cola noveboracensis Richardson, and some of Rafinesque’s names. 
Mr. Bailey describes as new two species and one subspecies. 
Mr. Osgood's * Revision of the Pocket Mice”? is an equally wel- 
come contribution, and has been prepared upon much the same lines, 
with equal advantages in the way of material and field experience. 
The pocket mice of the genus Perognathus are confined to a limited 
portion of North America, being found only west of the Mississippi, 
and ranging from the southern border of British Columbia south to 
the valley of Mexico. They are strictly nocturnal and live in bur- 
rows, are partial to arid regions and seem to thrive even in the most 
barren deserts. Their habits are hence not well known, as they are 
very shy and even difficult to trap. They are mouse-like in form, but 
only distantly related to the true rats and mice. Their most obvious 
character is the possession of cheek pouches which open externally. 
The pocket mice vary greatly in size, form, and in the nature of 
their pelage, which may be either soft or hispid ; but between the 
wide extremes there are so many closely connecting links that it is 
difficult to find any sharp lines of division, although two subgenera 
are fairly recognizable. The whole number of forms here recognized 
is 52 — 31 species and 21 additional subspecies, about equally divided 
between the subgenera Perognathus and Chztodipus. Of these, 
thirteen are here for the first time described. Out of a total of 61 
specific and subspecific names applied to forms of this group, 9 
are relegated to synonymy. Of these 61 names, it is interesting to 
note that 52 date from 1889 or later, and that of these, eight prove 
to be synonyms, three of them having become so through the identi- 
fication of older names thought ten years ago to be indeterminable, 
but since reéstablished on the basis of topotypes. 
A previous revision of this group was made in 1889 by Dr. C. 
Hart Merriam, on the basis of less than two hundred specimens — 
1 Revision of the Pocket Mice of the Genus Perognathus. By Wilfred H. 
Osgood, Assistant Biologist, Biological Survey, U. S. Department of Agriculture. 
Prepared under the direction of Dr. C. Hart Merriam, Chief of Division of Bio- 
logical Survey. North American Fauna, No. 18, pp. 1-72, Pls. I-IV, and 15 text- 
cuts. Issued Sept. 20, 1900. 
