age and extreme measurements of seven
adult males and six adult females of _P. ochraventer_ from
the type locality are, respectively, as follows: Total
length, 238.0 (227-249), 236.5 (226-248); length of tail,
124.4 (117-127), 122.2 (116-128); length of hind foot, 25.6
(24-26), 25.5 (25-26); length of ear from notch, 20.9
(20-21), 20.7 (20-21); greatest length of skull, 31.0
(30.6-31.9), 30.8 (30.5-31.0); basilar length, 23.3
(22.7-23.8), 23.4 (23.0-23.9); zygomatic breadth, 15.1
(14.6-15.7), 15.0 (14.9-15.2); post palatal length, 10.6
(10.5-10.9), 10.9 (10.5-11.2); interorbital breadth, 4.7
(4.5-4.9), 4.7 (4.6-4.8); mastoidal breadth, 12.8
(12.4-13.2), 12.8 (12.6-12.9); length of nasals, 11.6
(10.8-12.0), 11.6 (11.2-11.7); length of shelf of bony
palate, 4.7 (4.5-4.8), 4.6 (4.5-4.7); length of palatine
slits, 6.3 (6.0-6.5), 6.2 (6.0-6.4); length of diastema, 8.2
(8.0-8.5), 8.2 (8.1-8.4); alveolar length of upper
molariform tooth-row, 4.4 (4.3-4.6), 4.4 (4.3-4.5).

_Specimens examined_, 28, from the type locality.

~Oryzomys couesi aquaticus~ Allen

Coues Rice Rat

_Oryzomys aquaticus_ Allen, Bull. Amer. Mus. Nat. Hist.,
3:289, June 30, 1891. (Type from Brownsville, Cameron
County, Texas.)

_Oryzomys couesi aquaticus_ Goldman, N. Amer. Fauna, 43:39,
September 23, 1918.

_Specimens examined_, 2 as follows: 36 km. N and 10 km. W
Ciudad Victoria, 1 km. E El Barretal, on Rio Purificacion,
1; 70 km. [by highway] S Ciudad Victoria and 6 km. W of the
[Pan-American] highway [at El Carrizo], 1.

_Remarks._--The specimens, all immatures, are slightly darker than
topotypes of _O. c. aquaticus_, seemingly tending toward the darker _O.
c. peragrus_ Merriam to the southward. These records of occurrence
extend the known range of this subspecies approximately 210 miles to
the southward and increase the possibility of continuous distribution
between _O. c. aquaticus_ and _O. c. peragrus_.

The male obtained south of Ciudad Victoria was taken on January 12, by
William J. Shaldach, Jr., 200 yards within the tunnel of a mine at an
elevation of approximately 2600 feet. This was in the Sierra Gorda,
which is a part of the Sierra Madre Oriental.

~Oryzomys rostratus rostratus~ Merriam

Rice Rat

_Oryzomys rostratus_ Merriam, Proc. Washington Acad. Sci.,
3:293, July 26, 1901. (Typ