200 PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 
weather combined spoiled a great number. The abundance of 
Sigmodon on the island was also a hindrance to trapping Peromy- 
scus, as night after night they filled up the greater part of my traps, 
and their numbers were inexhaustible. During my wanderings 
over the sand hills of Anastasia Island, I never saw a living mouse, 
though I tried hard to find out where P. phasma spends the day, 
and, judging by their foot-prints, there must often have been scores 
of them within a few rods of me. The loose sand in most places 
would hardly permit of their making burrows, and even in the 
firmer parts, I found Tew holes that seemed to be occupied by them. 
The protective coloration of this species is so wonderful, that I 
believe all it need do is to lie still on the sand near some object, as 
a half buried log or a tuft of sea oats, in order to escape even the 
closest scrutiny. I did not take a single young example of 
P. phasma. and therefore do not know what the young in 
nursing pelage is like. 
P. phasma differs from its nearest ally, P. niveiventris , in its 
much paler coloring, in the greatly reduced width of the colored 
portion of the back, in the legs being white all around, and in having 
pure white markings on the upper part of the nose, over the eyes, 
and at the base of the ears. In nearly two hundred examples of 
P. niveiventris that I have examined, not one approaches P. 
phasma ; while the series of P. phasma is wonderfully constant 
in all the characters pointed out above. 
Peromyscus subgriseus subgriseus (Chapman). 
Sitomys niveiventris subgriseus Chapman, Bull. Amer. mus. nat. 
hist., 1893, p. 340. 
Type locality. Gainesville, Florida. 
The diminutive old field mouse is found in suitable situations all 
through central and western Florida. It lives in fields and open 
places, and probably before so much of its range was under culti¬ 
vation, was restricted to the sand hills and open drier prairies 
of interior Florida. I have never seen a specimen from eastern 
Florida and feel confident that, if it occurred there, I should have 
taken it. Neither do I know of any point where its range meets 
that of P. niveiventris , and even if some such place does exist, the 
two species are so different that intergradation is out of the 
question. 
