NORTH AMERICA AND THE WEST INDIES 97 



ish below; feet brownish gray, not dusky. Six adults averaged 

 in total length, 203 mm., about 8 inches; tail, 65; hind foot, 

 25.1. Skull, basal length, 31 mm.; zygomatic breadth, 19; 

 upper molar series, 8.7. 



When first described by Bailey this race was known only 

 from the type locality, where it lived in wet ground under tall 

 tules (Scirpus olneyi), in a little marsh surrounding a warm 

 spring. Here the mice had made extensive runways through 

 the mud and water. Kellogg (1918), in reviewing the meadow 

 mice of the calif ornicus group, points out that it is an outlying, 

 isolated form, a relict of what was doubtless in former times 

 a more or less continuously distributed species. "It is a re- 

 markable race because of its occurrence away from the main 

 mountain axes and in an area of extremely high summer 

 temperature" in southeastern California. Since assiduous 

 trapping at the original locality in May, 1917, failed to yield a 

 single specimen, Kellogg believed that it had "been extermi- 

 nated within recent years, as the type locality, a small tule 

 marsh near Shoshone, Inyo County, has been burnt over for 

 several consecutive years and is now being used as a hog 

 pasture." Nevertheless, it seems that a remnant persists, for 

 Dr. Joseph Grinnell writes in response to Dr. Francis Harper's 

 inquiries, in 1937, that it has been "rediscovered within the 

 last few years, not to be sure, at the type locality, but within a 

 few miles' radius, as a result of intensive search. This is to be 

 credited to Miss Annie M. Alexander, who found them in 

 exceedingly small numbers at two desert seepages, where, 

 however, the favoring conditions might at any time be wiped 

 out." On account of its living in such very localized swamps, 

 where a series of dry years or drainage and fire might at any 

 time destroy its habitat, the race is in a precarious state much 

 like that of an animal living on a few small islands where the 

 environment may become unsuitable through slight changes. 



GULL ISLAND VOLE 



MlCROTUS PENNSYLVANICUS NESOPHILUS Bailey 



Microtus nesophilus Bailey, Science, new ser., vol. 8, p. 782, Dec. 2, 1898 (Great Gull 



Island, at entrance to Long Island Sound, New York). 

 SYNONYM: Microtus insularis Bailey, Proc. Biol. Soc. Washington, vol. 12, p. 86, Apr. 



30, 1898 [not Lemmus insularis Nilsson = Microtus agrestis (Linnaeus)]. 



