irs inside the
pinna; dark tarsal stripe not extending onto hind foot; ears and hind
feet uniformly smaller; averaging smaller in cranial dimensions (but
there is considerable overlap), braincase less convex dorsally.

Measurements of the adult _anthonyi_ now available show that the
subspecies reaches a greater size than was apparent in the sample
available to Hooper. Consequently the three largest adults would be
identified as _R. mexicanus_ according to Hooper's key (1952:31),
rather than _R. gracilis_, and the three smallest adults could not be
unequivocably identified as either one species or the other.

The ranges of _R. gracilis_ and _R. mexicanus_ are allopatric except in
southern Guatemala where the ranges overlap. However, the two species
have not been taken there at the same place.

In comparison with May-taken adults of _R. g. harrisi_ from 3 mi. SW
Managua, Nicaragua, the adult _anthonyi_ average brighter (more orange)
in color (but two of the _anthonyi_ cannot be distinguished by color
when placed with the _harrisi_), and are larger in total length, length
of tail, and size of skull.

One female (KU 65400) contained two embryos that measured 18 mm. in
crown-rump length.

Average and extreme external and cranial measurements of the
six adults are: total length, 183.6 (170-198); length of
tail, 106.0 (95-113); length of hind foot, 18.0 (18); length
of ear from notch, 14.0 (14); total length of skull, 22.21
(21.4-22.8); zygomatic breadth, 11.20 (10.9-11.7); breadth
of braincase, 10.90 (10.3-11.4); depth of skull, 8.36
(8.0-9.0); length of rostrum, 7.60 (7.3-7.8); breadth of
rostrum, 4.24 (4.0-4.6); interorbital constriction, 3.78
(3.6-4.0); length of incisive foramen, 4.05 (3.8-4.3);
length of upper molar tooth-row, 3.28 (3.1-3.4). Weight in
grams of the adults averaged 14.3 (12-17).

~_Reithrodontomys gracilis gracilis_~ Allen and
Chapman.--GUATEMALA.--El Peten: Uaxactun, 1500 ft., 2 (KU
65384-85--April 3, 1955).

These specimens are the first of the subspecies to be recorded from
Guatemala. Uaxactun is near, but not within, the range of _R. g.
gracilis_ as mapped by Hooper (1952:131). The male, KU 65384, and
female, KU 65385, are adults with comparatively unworn molar teeth.
Respective external measurements are: total length, 178, 175; length of
tail, 106, 102; length of hind foot, 18.5, 19; length of ear from
notch, 14, 14.

~_Reithrodontomy