6G8 MR. E. R. ALSTON ON NEOTROPICAL SQUIRRELS. [June 18, 



middle of the back is considerably darker than the flanks ; and there 

 is some variety in the exact tint of the red wash on the tail. I can 

 confirm Mr. Allen's statement that this species (as well as /S. varia- 

 bilis and S. cestuans) have normally only one upper premolar. Dr. 

 Peters states, it is true, that the type of his " var. hoffmanni " had 

 two ; but the first was minute and only attached to the gum ; and 

 I have not been able to find more than one, either in dried skulls or 

 in spirit-specimens. 



IX. SCIURUS JESTUANS. 



Sciurus cestuans, Linnaeus, Syst. Nat. i. p. 88 (1/66). 



Myoxus guerlingus, Shaw, Gen. Zool. ii. p. 171, pi. clvi. (1801). 



Sciurus gilvigularis, Natterer ap. Wagner, Abh. Bayer. Ak. v. 

 p. 283 (1850). 



*Macroxus leucogaster, Gray, Ann. & Mag. Nat. Hist. ser. 3, 

 xx. p. 430 (18G7, nee F. Cuv.). 



*Macroxus irroratus, Gray, torn. cit. p. 431. 



* Macroxus Jlaviventris, Castelnau ap. Gray, torn. cit. p. 432. 



(Sciurus cestuans, var. cestuans, Allen, Mon. N.-Am. Rodent, 

 p. 756, 1877). 



Hab. Guiana ; Brazil ; Eastern Peru ; Bolivia. 



Average length about 7'25 inches, of tail-vertebrae 7 inches. One 

 upper premolar. Upper parts olive, rather lighter and more fulvous 

 than in the last species ; lower parts fulvous, greyish, or white ; tail 

 black, more or less washed with pale fulvous, the hairs pale brown, 

 banded with black and tipped with pale faded yellow. 



I have little to add to Mr. Allen's critical notes on this well-known 

 Squirrel. Gray states, in his description of his M. leucogaster (not 

 to be confounded with F. C'uvier's species of that name 1 ), that the 

 hairs of the lower parts are " white to the base ;" this is not the 

 case, though the dusky colour at the roots is little developed on the 

 chest. M. irroratus must also be placed here, although the original 

 description is such that Mr. Allen unhesitatingly referred it to the 

 last species ; and M.flaviventer is to me quite undistinguishable from 

 the ordinary type of S. cestuans. S. pusillus, Geoffr., and Macrotus 

 kuhlii, Gr., are considered by Mr. Allen to be the young of the 

 present species ; but I believe them to be quite distinct 2 . 



X. Sciurus deppei. 



* Sciurus deppei, Peters, Monatsb. Ak. Berl. 1863, p. 654. 



*Macroxus tephrogaster, Gray, Ann. & Mag. Nat. Hist. ser. 3, 

 xx. p. 431. 



*Macroxus tceniurus, Gray, loc. cit. 



*Macroxus medellinensis, Gray, op. cit. ser. 4, x. p. 408 (1872). 



(Sciurus tephrogaster, Allen, Mon. N.-Am. Rodent, p. 763 (1877)). 



Hab. Mexico ; Honduras ; Guatemala ; Columbia. 



Average length nearly 9 inches, of tail-vertebrae 7'25 inches. Two 

 upper premolars. Upper parts dark olive, often darker along the 



1 Cf. anted, p. 660. 2 Cf. infra, p. 670. 



