"Parietal breadth" is the breadth, across the braincase, taken approximately half way between the squamosal root of the zygoma and the external auditory meatus, where there is a lateral bulge in the squamosal bone. On each side of the skull, the calipers rest on the squamosal bone, not on the parietal bone.
"Diameter of bullae" excludes the paroccipital process and was taken from the anteriormost part of a tympanic bulla, posterolaterally to the part of that same bulla, that is exposed at the lateral side of the base of the paroccipital process.
Specimens examined.—Total, four, all from Tamaulipas, Mexico, as follows: 88 mi. S and 10 mi. W Matamoros, 3; 90 mi. S and 10 mi. W Matamoros, 1.
Transmitted February 20, 1951.
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