1878.] MR. E. R. ALSTON ON NEOTROPICAL SQUIRRELS. 667 



dorffi and 8. tricolor both refer to the forms in which the upper 



parts are more or less uniformly grizzled ; while 8. morio, S. »//<*- Uk^m^m 



niyer, and M. fumigatus, are all more or less melauistic varieties. 



VIII. SciURUS GRISEOGENYS. 



*Sciurus cestuans, var. hoffmanni, Peters, Monatsb. Ak. Berl. 

 1863, p. 654. 



*8ciurus hyporrhodus, Grav, Ann. & Mag. Nat. Hist. ser. 3, xx. 

 p. 419(1867). 



*Macroxus xanthotus, Gray, torn. cit. p. 429. 



*Macroxus griseogena, Gray, torn. cit. p. 429. 



(8ciurus cestuans, var. rvfo-niger, Allen, Mon. N.-Am. Rodent. 

 p. 757.) 



Hab.Ecna.dor; Columbia ; Venezuela; Panama; Veragua; Costa 

 Rica ; Nicaragua. 



Length about 9 inches, of tail-vertebrse 8 inches. One upper pre- 

 molar. Upper parts dark olive, the hairs dusky, very minutely an- 

 nulated with rufous or fulvous ; lower parts bright orange or rufous ; 

 tail black, more or less washed with bright red or deep orange, the 

 hairs reddish brown banded with black and tipped more or less 

 broadly with rufous. 



Mr. Allen, in his monograph, regards this Squirrel as a "variety " 

 or geographical race of the next species, differing in its uniformly 

 larger size and strikingly in the coloration of its tail. In a sub- 

 sequent letter to me, he says : — " It would perhaps be just as well 

 to recognize it as entitled to specific rank, altbough I still feel sure 

 of their intergradation." That such connecting links may yet be 

 found seems very probable ; but I have not been able to find such 

 in the very large series which I have examined, and am consequently 

 compelled to keep them provisionally distinct. 



Unfortunately Mr. Allen has identified this species with Pucheran's 

 S. rufo-niger, which, as will be seen presently, is a much smaller and 

 quite distinct species'. Dr. Peters described it only as a variety of 

 8. cestuans ; and though specimens in the Berlin Museum are la- 

 belled " Sciurus hoffmanni," the name remains a manuscript one. 

 Of Gray's three titles I have adopted griseogena (more correctly gri- 

 seoge?iys) as being simultaneous in date with the others, and as in- 

 dicating the typical form. His S. hyporrhodus is founded on an 

 example from Santa Fe de Bogota, and is characterized by its 

 long soft fur and hairy ears, peculiarities easily explained when 

 we remember that that city stands at an elevation of over 8800 

 feet, and is overlooked by lofty mountains. Macroxus xanthotus 

 is undoubtedly an immature animal, as is proved by the dentition 

 of the type specimen. By some curious error Gray's account of 

 this last has been printed after that of M. brunneo-niger, instead of 

 after M. griseogena ; so that the remark, "very like the former " &c, 

 naturally led Mr. Allen to refer the synonym to 8. gerrardi. 



S. griseogenys varies very little in colour : in some examples the 



1 Cf. infra, p. GOO. 



43* 



