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Show 1878.] MR. E. R. ALSTON ON NEOTROPICAL SQUIRRELS. 669 middle of the back ; lower parts white, greyish white, or light fulvous ; tail black, lightly washed with white, the hairs fulvous, with black bands 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 S. deppei, which he doubtfully referred to the southern form of S. carolinensis1. An examination of the types of S. deppei, M. tephrogaster, M. teeni-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. teeniurus the lower parts are washed with fulvous ; 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. Intermediate examples occur ; and the whole range of variation between the extremes is comparatively trifling. As already observed2, AL fraseri, Gr., was so insufficiently described that Mr. Allen was led to identify it with the present species, which is about half its size and totally different in coloration. XI. SCIURUS RUFO-NIGER. *Sciurus rufo-niger, Pucheran, Rev. de Zool. 1845, p. 336. ^Sciurus chrysosurus, Pucheran, torn. cit. p. 337. *Macroxus tephrogaster minor, Gray, MS. (Mus. Brit.). Hab. Columbia; Panama; Veragua. Average length about 5*50 inches, of tail-vertebrae 3*75 inches. Two upper premolars. Upper parts dark olive, the hairs very minutely tipped with fulvous ; breast bright rufous, rest of lower parts like the upper, but 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 5. deppei; and I soon recognized 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 ou 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 in the tail being more rufous. • Tom. cit. p. 710. 2 Of- »»fea, P- 665. |