pS NELSON 



Color. — Entire dorsal surface, including top of nose and base of tail, 

 vmiform pale yellowish gray ; sides of head dull, dark buffy yellow, 

 grizzled on cheeks with gray and black, sometimes with a slight red- 

 dish shade ; ring around eye buffy ; ears dingy rusty, or buffy yellow ; 

 feet dark yellowish buffy shading into gray on upper part of fore legs ; 

 outside of hind legs like back but with a buffy or dull rusty wash near 

 feet ; underparts varying from orange buff to pale, slightly reddish 

 rusty ; tail above, grizzled black and gray with a thin wash of grayish 

 or pale grayish yellow ; below, with broad median area of rusty fer- 

 ruginous or yellowish rusty, often grizzled with black, a narrow black 

 border and thin edging of grayish or pale yellowish. Hairs on back 

 black, with broad subterminal and basal or sub-basal rings of pale yel- 

 lowish or buffy ; along sides of body often tipped with white. 



Variation. — The series at hand shows very slight individual and 

 little if any seasonal variation. The difference lies mainly in the in- 

 tensity of the yellow or rusty and the amount of grayness on the back, 



Measurements. — Average of five adults from region of type locality : 

 total length 482.2 ; tail vertebrae 234; hind foot 65.2. 



Cranial characters. — Premolars \. Compared with S. ludovici- 

 anus the skull (pi. I, fig. i), is very much smaller. Two adult skulls 

 from Fort Clark, Texas, average : basal length 50 ; palatal length 25.5 ; 

 interorbital breadth 18; zygomatic breadth 33.5; length of upper 

 molar series 10.5. 



Specimens examitied. — Fourteen : from near the mouth of Devils 

 River, Fort Clark, and Nueces River, Texas. 



Subgenus GUERLINGUETUS Gray. (p1. I, fig. 7.) 



SCIURUS ^STUANS HOFFMANNI Peters. 

 Hoffmann's Squirrel. 



Sciurus cestuans var. koffmaftni Vki^^S, Monatsber. K. Akad. Wiss., Berlin, 



1863, pp. 654-655 ; Thomas, Proc. Zool. Soc. London, 1880, p. 401 



{Macroxus griseogena Gray, referred to this form). 

 Macroxus xanthotus Gray, Ann. & Mag. Nat. Hist., 3d ser., xx, p. 429, 



1867. 

 Macroxus griseogena Gray, Ann. & Mag. Nat. Hist., 3d sen, xx, pp. 429- 



430, 1867 (part : Costa Rica). 

 Sciurus ceshians var. rufoniger h.iA.Y.'n, Mon. N. Am. Rodentia, pp. 757-763, 



1877 (part : Costa Rica). 

 Sciurus griseoge7iys Alston, Proc. Zool. Soc. London, pp. 667-668, 1878 



(part : Costa Rica, Veragua and Panama.) 

 Sciurus hoffmanni Allen,- Bull. U. S. Geol. Survey Terr. iv. pp. 885-886, 



1878. 



