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Show 666 MR. E. R. ALSTON ON NEOTROPICAL SQUIRRELS. [June 18, ing; tail black, washed with bright-red orange, often very bushy. Pelage rather harsh and sparse, ears high and narrow. Here, again, the greater amount of material at m y disposal compels me to go beyond Mr. Allen in the identification of nominal species. Most of "the above synonyms were brought together by him under the name of S. variabilis; but S. gerrardi and S. rufo-niger were kept separate under the former title. The principal points on which he rested were the smaller size and shorter ears of S. gerrardi; but on examination of a sufficient series, I have not been able to find any constancy in the proportions of the ears, while the difference in size totally disappears, as is shown by the following series of measurements-9*50, 9*75, 1000, 10*25, 10*75, 11, II 50, 11*75, 12*00, 12*75, 1300. The smaller specimens (S. variabilis, S. gerrardi, &c.) appear to prevail towards the north : but this is not constant; for a Santa-Martha example measures over 12 inches, while others from Brazil are under 10 in., although evidently adult. Nor is it constantly connected with any of the numerous varieties of coloration-rufous, grizzled, and melanistic specimens occurring of all sizes. The range of these variations of colour is not nearly so great as in S. hypopyrrhus; and they seem to resolve themselves into three primary groups, namely :- 1. The morio type. Upper and lower parts black, only slightly ringed with rufous or fulvous, tail black, either entirely or slightly washed with red. Of this melanistic form no two specimens agree exactly in the proportion of red ; and every step is present leading into 2. The variabilis type. Upper parts red, more or less varied with black-but the rufous tint prevailing, especially on the flanks ; lower parts pure white, fulvous, or pale rufous; tail (either narrow or bushy) black, strongly washed with bright rufous or orange. Here we have an endless series of minor variations, from the very brilliant black and red specimens sent from the Rio Napo to the British Museum, and the bright rufous Columbian form, through more and more greyish red specimens, till we find ourselves in 3. The langsdorffi type. Upper parts reddish or yellowish grizzled, the hairs being pretty uniformly ringed with black and red or black and yellow ; lower parts and tail as in the last. Each of these styles appears to prevail in certain localities: thus the melanistic form has been found on the Upper Amazons by Mr. Bates and by Castelnau and Deville, the rufous type on the Bio Negro and Rio Madeira by Natterer, and the grizzled in Northwestern Brazil by Spix. But there seems to be no regularity in their distribution ; and I have seen both grizzled and red specimens from Panama, Venezuela, Columbia, and North-eastern Peru. The oldest name, and therefore the one here adopted, is S. variabilis, given in 1832 by Isidore Geoffroy to small red specimens from Columbia, and strictly synonymous with Gray's S. gerrardi; while S. igniventris and 8. pyrrhonotus were M S . names of Natterer's, applied by Wagner to other varieties of the rufous type. S. langs- |