80IUIiIDJ5— SPEKMOrHIJ.US MEXICAN US. 



869 



the sides ; ring surrounding the eye am' lower edge of checks white ; head 

 above finely mixed white, black, and yellowish ; tail above varied centrally 

 with black and yellowish-white, with an indistinct black border broadly edged 

 with yellowish-white ; below, brownis'i-white centrally, with a distinct sub- 

 terminal band of black and a broad edging of brownish-white. The hairs 

 individually have a narrow black bar nt the base, followed by alternate bars of 

 browuish-white and black, three of each, the terminal one being whitish. 



This species varies as usual more or less in cespect to general color, that 

 of the dorsal surface ranging frori dull ashy-brown to chestnut. The num- 

 ber of rows of white spots varies from nine to thirteen, but either nine or 

 eleven is the more common number, the two or three central ones on either 

 side of the median line being generally much more distinct than the outer 

 ones. In the latter, the white spots are longer and nearer together, forming 

 sometimes an almost uninterrupted line. The ears are very small, but dis- 

 tinct. The tail-vertebrae alone are rather more than half the length of the 

 head and body; claws long, that of the thumb quite large. Soles nearly 

 naked. Pelage coarse and /itiff, the hairs mostly grooved above. 



In size and proportions, as well as in the pattern of coloration, this 

 species more resembles il. trideceinlineatus than any other, but differs from 

 it quite markedly in many details. The tail is longer and more bushy, with 

 three narrow longitu : »1 lines of black beneath instead of one very broad 

 one (in addition, there is, however, in S. tridecemlineatus, a narrow basal 

 one); the general color above is much lighter and of a quite different shade, 

 with interrupted lines of whitish spots instead of six or more narrow, contin- 

 uous, yellowish-whit J stri[>es, with a similar number of interrupted ones be- 

 tween them ; there are also well-marked diiferences in the skull. In respect 

 to cranial charactf-rs, however, S. mexicanus finds also its nearest ally ih S. 

 tridecemlineatus. 



In respect io coloration, there is considerable resemblance between 8. 

 mexicanus and iS. spilosoma ; but, in other features, the two species difier 

 widely, as alrefidy noticed in the account of S. spilosoma. 



This 8pe';ies was first recognizably described and figured by Lichtenstein, 

 about 1830, from a specimen collected by Herr F. Deppe, in July, 1826, in 

 the neighborhood of Toluca, Mexico. Erxleben, in 1777, characterized a 

 " Sciurus tnexicanun", based on Fernandez's description of his " Tlamototli", 



