SQUIRRELS OF MEXICO AND CENTRAL AMERICA 97 



of legs and feet are paler. This specimen is exceptionally gray on 

 the back, as it lacks the usual well defined yellowish area on rump. 

 Several worn summer specimens from Huachuca have the area about 

 the mouth and inside of fore feet and legs stained deep brown from 

 the juice of walnut shells, and the underparts of a number of speci- 

 mens are dingy buffy, probably due to the same cause. 



Measurements . — Average of four adults from type locality : total 

 length 517; tail vertebrie 247; hind foot 70.5. 



Cranial characters. — Premolars \. Skull similar to that of S. ocu- 

 latus^ but rostrum heavier ; parietal region slightly more inflated ; oc- 

 ciput higher and narrower ; foramen magnum higher, narrower and 

 obtusely triangular; audital bullae decidedly smaller. Four adult 

 skulls from type localit}^ average : basal length 53.5; palatal length 

 27.5; interorbital breadth 19.9; zygomatic breadth 36.5; length of 

 upper molar series 10.9. Four adult skulls of arizonensis from near 

 type locality average : basal length 53.3; palatal length 37.1 ; inter- 

 orbital breadth 30.1 ; zygomatic breadth 36.4; length of upper molar 

 series 11.4. 



General notes. — This is not a strongly marked subspecies but the 

 separation of the yellowish dorsal area by the gray band across the 

 shoulders and neck seems to be constant and is accompanied by dif- 

 ferences in size. A specimen from the Santa Catalina Mountains, 

 Arizona, between the type localities of arizonensis and huachuca^ is 

 exactly intermediate between the two forms. 



Specimens examined. — Twenty-six : from Huachuca Mountains, 

 Arizona, and Sonora, Mexico (33 miles south of Nogales). 



Subgenus PARASCIURUS Trouessart. (p1. I, fig. i.) 



SCIURUS LUDOVICIANUS LIMITIS Baird. 

 Texas Fox Squirrel. 



Sciurus limiiis Baird, Proc. Acad. Nat. Sci. Phila., vii, p. 331, 1855 ; 



Mamm. N. Am., p. 256, 1857. 

 Sciurus niger V2ir. ludovicianiis Allen, Mon. N. Am. Rodentia, pp. 724-731, 



1877 (part : southwest Texas and Nuevo Leon, Mexico). 



Type locality. — Devils River, Texas. Type no. 351 U. S. Na- 

 tional Museum. 



Distribution. — Wooded parts of Lower Sonoran zone in southwest- 

 ern Texas and adjacent parts of Nuevo Leon and Coahuila, Mexico. 



Characters. — Similar to S. ludovicia?ius but considerably smaller, 

 with slenderer tail, thinner pelage and paler colors. Pelage thin, hairs 

 of back rather harsh ; under fur thin. Teats : p. i a. |- i. \. 



