N 
N 
N 
THE AMERICAN NATURALIST. [Vor. XXXV. 
familiarly typified by our common “meadow mice” of the Eastern 
States. The group is divisible into several well-marked subgenera, 
formerly generally known under the generic term “ Arvicola,” which 
has had to give way to the less known but older term “ Microtus.” 
The group is especially distinctive of the northern hemisphere north 
of the tropics, and is found throughout North America from the 
mountains of Guatemala and southern Mexico northward, increasing 
numerically, both in species and individuals, from the south north- 
ward till it reaches its greatest abundance in the middle and colder 
temperate zones, again declining thence northward to the Arctic 
coast. They are vegetable feeders, and often do considerable dam- 
age to trees and crops ; they are active in the winter, forming long 
burrows or tunnels under the snow ; they are also very prolific, breed- 
ing several times a year, young being found throughout the warmer 
months. 
The seventy species and subspecies recognized by Mr. Bailey are 
arranged in nine subgenera ; between the extreme forms the differ- 
ences are strongly marked, but the intermediate forms present grad- 
ual stages of intergradation. The subgenus Neofiber, of Florida, 
embracing the round-tailed muskrat, and the subgenus Lagurus, of 
the semi-arid districts of the northwestern United States, present the 
most striking contrast, not only in size but in many other features. 
The former is perhaps the largest known vole, while the latter group 
includes the smallest. 
Mr. Bailey’s paper, being a synopsis rather than a monograph, 
leaves much to be desired in point of detail, but is admirable in its 
way, and covers the ground with as much fullness as his prescribed 
limits would permit. Of the twenty-six synonyms cited, it is notice- 
able that thirteen relate to our common eastern meadow mouse, and 
date from the early authors, while two other eastern species furnish 
three others, also of early date. Only six of the remaining ten are 
of recent date, showing that of some fifty-five forms described within . 
the last ten years, by nine different authors, forty-eight meet with 
Mr. Bailey’s approval. Four of the remaining seven are identified 
with earlier names which for many years have been considered 
indeterminable, but which Mr. Bailey claims to have established on 
the basis of topotypes. 
While he may be correct in these determinations, it would have 
been of interest to his fellow-specialists if he had stated the basis of 
his determination of certain type localities, notably those of Richard- 
son's species, described as from the * Rocky Mountains," or similarly 
