134 Proceedings of the Biological Society of Washington. 



more conspicuously below basioccipital ; postorbital processes stout and 

 tapering as in aztecus, not peg-like as in P.f. cMriquensis. 



Measurements. — Type: Total length, 1050; tail vertebrse, 536; hind 

 foot, 110. An adult male topotype: 950; 490; 103. Skull (type) : Great- 

 est length, 93.5; condylo-basal length, 89.1; zygomatic breadth, 61.9; 

 interorbital breadth, 22.3; breadth of rostrum, 23.7; breadth across 

 mastoid processes, 46.3; alveolar length of upper molariform tooth- 

 row, 21. 



Remarks. — An arm of the general range of the Polos flavus group 

 extends northward in the tropical belt along the Pacific coast west of the 

 high mountains of the interior to Papayo ( near Acapulco ) , Guerrero, and 

 perhaps farther. Specimens from this region do not differ appreciably in 

 general size or color from P. f. aztecus of eastern Mexico, but the cranial 

 characters are distinctive. 



Specimens examined. — Four, from localities in Guerrero as follows: 

 Near Ometepec (type locality), 3; Papayo, 1. 



Qeomys personatus tropicalis subsp. nov. 



TAMAULIPAS POCKET GOPHER. 



7)/pe from Alta Mira, Tamaulipas, Mexico. No. 92,946, male adult, 

 U. S. National Museum (Biological Survey Collection), collected by E. A. 

 Goldman, April 18, 1898. Original number 12,320. 



General characters. — Similar in color to G. p. personatus and G. p. 

 fallax; size rather small, about as in fallax, much smaller than in typi- 

 cal personatus; skull differing in detail from both, especially in the 

 anteriorly spreading zygomata, slenderer posterior ends of premaxillse, 

 and narrower interpterygoid fossa. 



Color. — Type (somewhat worn pelage) : General color of upperparts 

 between cinnamon and cinnamon-buff, fading to light buff along lower 

 part of sides; the top of head and back thinly overlaid with brown; 

 underparts white ; feet thinly clothed with short whitish hairs ; tail nearly 

 naked; flesh-colored. 



Skull. — Similar in size to that of G. p. fallax, much smaller than that 

 of G. p. personatus; zygomata narrowing posteriorly, the sides less nearly 

 parallel, and ascending branches of premaxillae narrower, more tapering 

 posteriorly than in fallax or typical personatus; interpterygoid fossa 

 narrow ; mastoid and audital bullpe shrunken in appearance much as in 

 typical personatus, not swollen or rounded as in fallax. 



Measurements. — Type: Total length, 270; tail vertebrse, 86; hind foot, 

 33. Skull (type): Condylo-basal length, 46.9; zygomatic breadth, 30.4; 

 interorbital breadth, 6.2; length of nasals, 17,6; alveolar length of upper 

 molar series, 10. 



Remarks. — No specimens of the genus Geomys, as now restricted, have 

 hitherto been recorded from Mexico. The discovery of a form of G. 

 personatus in extreme southern Tamaulipas, therefore, materially extends 

 the known range of the group to the southward. 



Specimens examined. — Twelve, all from the type locality. 



