1908] Grinnell.—Biota of the San Bernardino Mountains. 149 
eight adult specimens in the cienaga at the head of the South 
Fork of the Santa Ana, 8500 feet altitude, June 28 to 30, 1905. 
They were taken among reeking-wet grass tufts on the banks of 
the icy streamlets which issue from the mountain sides. June 
19, 1907, a Microtus, probably of this species, was seen at Dry 
lake, 9000 feet altitude, and fresh burrows noted among the 
Symphoricarpus bushes along the west bank. We trapped there 
in 1905 without finding meadow mice. June 11, 1906, I found 
a nest under the end of a drift log in a clover bed five feet from 
the stream near the mouth of South Fork. This nest was of the 
usual globular style, of fine dried grass blades, and contained 
three newly-born young with eyes yet closed. There was a con- 
spicuous system of runways through the clover down to the 
water’s edge, but the female parent, which left the nest as the 
log was turned over and was thoroughly frightened, would not, 
as I had expected, take to the water as an avenue of escape. This 
example was preserved and seems to me to be WM. mordaax ber- 
nardinus, rather than californicus, though down within the zonal 
range of the latter. A few, at least, of this species were taken 
by us the latter part of July in a certain cienaga near Bluff lake, 
7500 feet, along with Microtus californicus. 
Out of my series of seventy-four San Bernardino mountain 
meadow mice about one-third are immature, and even of the re- 
mainder I must confess my inability to allocate several under 
one or the other category. I sent two of the mordax type (from 
the head of South Fork, where that form only was found) to 
Dr. C. Hart Merriam. He wrote me under date of January 14, 
1907, that they belonged to a new subspecies collected several 
years ago for the Biological Survey by F. Stephens on the ridge 
south of Bear valley at an altitude of 7500 feet. This was prob- 
ably in the vicinity of Bluff lake. Dr. Merriam further stated 
that he had deseribed the form under the name Microtus mordax 
bernardinus, but was holding the description to publish with 
others later in the year. (The form has since been described, in 
the Proceedings of the Biological Society of Washington, Vol. 
XXI, June 9, 1908, p. 145.) 
