1878.] MR. E. R. ALSTON ON NEOTROPICAL SQUIRRELS. 669 



middle of the back ; lower parts white, greyish white, or light ful- 

 vous ; tail black, lightly washed with white, the hairs fulvous, with 

 black bauds and short pure white tips. 



Mr. Allen was led to admit the specific validity of this Squirrel, 

 on finding that it differed from the last two in having normally two 

 well-developed upper premolars ; and the specimens which I have 

 been able to examine confirm his observation. He failed, however, 

 to recognize this species in Dr. Peters's description of his & deppei, 

 which he doubtfully referred to the southern form of S. carolinensis 1 '. 

 An examination of the types of S. deppei, M. tephrogaster, M. tceni- 

 urus and M. medellinensis convinces me that they are all strictly 

 synonymous, the species presenting but little variation in coloration. 

 In S. deppei and M. taniurus the lower parts are washed with ful- 

 vous ; in M. tephrogaster they are greyish white ; while the types of 

 M. medellinensis are smaller and have the middle of the back 

 nearly black, exactly as in many specimens of S. griseogenys. In- 

 termediate examples occur ; and the whole range of variation between 

 the extremes is comparatively trifling. 



As already observed 2 , M. fraseri, Gr., was so insufficiently de- 

 scribed that Mr. Allen was led to identify it with the present species, 

 which is about half its size and totally different in coloration. 



XI. SciURTJS RUFO-NHSfitt. CKT^S ©SvY H &• 



*Sciurus rufo-niger, Pucherau, Rev. de Zool. 1845, p. 336{<*t<» &Huk\ 



*Sciurus chrysosurvs, Pucheran, torn. cit. p. 337. 



*Macroxus tephrogaster minor, Gray, MS. (Mus. Brit.). 



Uab. Columbia ; Panama ; Veragua. 



Average length about 5"50 inches, of tail-vertebrae 375 inches. 

 Two upper premolars. Upper parts dark olive, the hairs very mi- 

 nutely tipped^wtth fulvous ; breast bright rufous, rest of lower parts 

 like the upper, hut paler ; tail nearly uniform with the back, the 

 hairs reddish fulvous, barred with black and minutely tipped with 

 pale yellow or white. 



On examining the type of Pucheran's S. rufo-niger in the Paris 

 Museum, I found that it was not identical with S. griseogenys, as 

 Mr. Allen supposed, but rather allied to <S. deppei ; and I soon recog- 

 nized in it a small Squirrel of which I had seen several specimens 

 from Panama^ and which I had begun to fear would require a new 

 name. These examples prove to agree further with 8. deppei in 

 having two upper premolars, but differ in being more than one third 

 smaller, in the colour of the lower parts (which are only paler than 

 the upper, save on the breast), and in the tail being nearly uniform 

 in colour with the back (the hairs having only very minute white or 

 yellow tips). Specimens in the British Museum are labelled M. 

 tephrogaster minor ; but I cannot doubt the distinctness of the form. 

 The type of S. rufoniger has the middle of the back nearly black ; 

 while that of M. chrysosurus appears to be a variety, merely differing 

 iu the tail being more rufous. 



1 Tom. cit. p. 710. a qf. anteh, p. 0(35. 



