r.

From _S. f. similis_ (holotype and three topotypes), _S. n. grangeri_
(eight practical topotypes from Redfern, South Dakota) differ as
follows: Throat patch darker; hind foot shorter; ear (dry) from notch
longer; rostrum narrower; posterior extension of supraorbital process
enclosing a longer and wider space between it and the braincase;
superior border of premaxilla straight in profile instead of convex
dorsally; tympanic bullae more inflated; external auditory meatus larger
(diameter of the meatus more, instead of less, than crown length of
upper molars); posterior border of palate without, instead of with,
spine.

Specimens of the two species from places as near each other as extreme
southeastern Montana (_S. f. similis_ from Boxelder Creek, Capitol and
the Little Missouri River) and Devils Tower, Wyoming (_S. n. grangeri_),
seem not to differ in the length of the hind foot and the ear and in the
color of the spot on the chest. Also, the presence or absence of the
spine on the posterior margin of the palate is subject to individual
variation in these specimens but the other cranial differences,
mentioned above, still are apparent. These same cranial differences are
readily apparent between specimens of the two species taken only five
miles apart in eastern Wyoming (for the precise localities, see the
following paragraph). It is concluded, therefore, that _S. f. similis_
and _S. n. grangeri_ do not inter-grade along the eastern base of the
Rocky Mountains.

Data on specimens from Laramie County in eastern Wyoming show that _S.
f. similis_ is a heavier animal than _S. n. grangeri_ and also that
_similis_ molts earlier. For example, an adult female (K.U. No. 15936)
taken on July 13, 1945, three miles east of Horse Creek P.O., 6400 ft.,
weighed 1374 grams and is in fresh pelage, whereas an adult female of
_S. n. grangeri_ (K.U. No. 15935), taken on July 17, 1945, two miles
west of Horse Creek P.O., 6600 ft., weighed only 1149 grams, and still
has some of the worn winter pelage on the upper parts.

Sylvilagus floridanus holzneri (Mearns)

1896. _Lepus sylvaticus holzneri_ Mearns, Proc. U.S. Nat. Mus.,
18:554, June 24.

1904. _Sylvilagus floridanus holzneri_, Lyon, Smithsonian Miscl.
Coll., 45:336, June 15.

Examination of cottontail rabbits from Arizona in the Biological Surveys
Collection and the United States National Museum indicates that
_Sylvilagus audubonii_ can be distinguished fr