On the Mexican Represeniatlm o/'Sciurus Abevti. 49 



(greatest len.gth of ridge of lioofs above, both fore and hind, 

 about 20 millim.). 



Skullj as compared with an equally fully adult male skull of 

 G. nigrifrons, that of the type, rougher and more swollen in 

 the frontal region ; muzzle shorter and more conical, broader 

 across the posterior ends of the nasals ; parietal region longer ; 

 orbit smaller and more exactly circular ; median notch of 

 palate but little surpassing the lateral ones ; bulla3 decidedly 

 smaller. As to skull-dimensions, those given in my mono- 

 graph as those of "(7. nataleiisis ((^) " (really this Malindi 

 skull of C. Harveyi) may be compared with those of the 

 C. nigrifrons on the page following. 



This new species may be inserted in the synopsis of species 

 in the above-quoted monograph (p. 415) as follows : — 



a*. Darker markings shining black or 

 brown. 

 rt^ Back uniform rufous, no dorsal 

 stripe, 

 a". Ground-colour dark chestnut 

 above and below ; hoofs elon- 

 gated 5. C. nigrifrons, Gr. 



b^. Ground-colour pale bay, lighter 

 below ; chin white ; hoofs not 



elongated 5 A. C. Harveyi, Thos. 



¥. Back with a black dorsal stripe, &c. 



X. — On the Mexican Representative o/Sciurus Aberti. 

 By Oldfield Thomas. 



In 1882 * two squirrels sent from Durango, Central Mexico, 

 by Mr. A. Forrer were referred by rae to Sciurus Aberti^ 

 Woodh., a species previously only known from Colorado, 

 Arizona, and New Mexico, and which 1 presumed to extend 

 southwards down the high lands of the Sierra Madre as far as 

 the point at which Mr. Forrer found it. Some doubt has 

 been recently thrown on this determination, and I have there- 

 fore now made a renewed examination of Mr. Forrer's beauti- 

 ful skins. This examination leads me to the conclusion that, 

 although the identity of the Durango animals with S. Aberti 

 should still be maintained so far as regards the species, using 

 this word in the larger sense to which English zoologists are 

 accustomed, yet there is sufficient difference in their detailed 

 coloration to necessitate their being considered as belonging 



* P. Z. S. 1882, p. 372. 

 Ann. tfc Mag. N. Hist. Ser. 6. Vol. xi. 4 



