1889. _Geomys personatus_ True, Proc. U. S. Nat. Mus.,
11:159 for 1888, January 5, type from Padre Island, Cameron
County, Texas.
_Distribution in Tamaulipas._--Known only from the barrier
beach in northeastern part of state.
The specimens examined are referred, tentatively, to _Geomys personatus
personatus_ on geographic grounds. They average smaller in all
measurements than _personatus_ (but are larger than _G. p.
megapotamus_), do not have the sagittal crest that usually is present
in _personatus_, and the shape of the pterygoid bones is distinctive.
In _personatus_ and _megapotamus_ the ventral border of the pterygoids
(in lateral view) is convex instead of nearly straight as in specimens
from the barrier beach. The specimens recorded here are all that are
known of _G. personatus_ (see account of _G. tropicalis_) from Mexico.
_Measurements._--Average and extreme external measurements
of five females from 73 miles south of Washington Beach are
as follows: 266.8 (263-271); 94.8 (91-98); 34 (33-35).
Cranial measurements of two males (89038, 89032) and average
and extremes of five females are respectively: basal length,
49.1, 46.6, 45.9 (44.2-46.8); basilar length, 42.9, 40.0,
39.8 (38.0-40.8); zygomatic breadth, 29.6, 28.3, 28.0
(25.7-29.9); squamosal breadth, 27.8, 25.9, 26.2
(23.8-25.4); interorbital constriction, 7.4, 6.9, 7.3
(6.7-7.8); alveolar length of maxillary tooth-row, 10.3,
9.2, 9.4 (9.1-9.7).
_Records of occurrence._--Specimens examined, 17: 35 mi. SSE
Matamoros, 8; 33 mi. S Washington Beach, 1; 73 mi. S
Washington Beach, 8.
Additional record: 4 mi. S Washington Beach (Selander _et
al._, 1962:335--possibly fragmentary skeletal remains never
catalogued in any research collection).
=Geomys tropicalis= Goldman