92 SCIURUS HUDSONIUS. 



And [this is a rule with only a few exceptions. Here more 

 than ever the accurate knowledge of the specimens is the 

 knowledge of the species. Therefore I abstain from diag- 

 noses of the several species, which moreover sufficiently 

 have been given by Allen and Alston , but on the other 

 hand I will endeavor to describe in terms as short as pos- 

 sible every specimen , which sliows an aberrant or remar- 

 kable variation in its mode of coloration or otherwise. 



Grooved incisors, so characteristic in some African and 

 Indian Squirrels, are not noticed in American species of 

 this group. In two of our specimens of Sciu7'us chrysuros 

 Pucheran , however the upper incisors show a grooving : 

 as they are from Medellin and agree in all other respects 

 entirely with the description of the type-specimen of Gray's 

 medellinensis , I thought that this author had overlooked 

 it, and wrote to Mr. Oldfield Thomas of the British Mu- 

 seum in order to examine the type: he kindly informed 

 me however that the specimens oi medellinensis Gyhj in thai 

 collection show no trace of a grooving. I thus incline to 

 believe that in this case we must look upon it as an in- 

 dividual particularity. 



Skeletons of American Squirrels seem to be very rare in 

 Musea : we only possess a single of Sciurus aestuans : it presents 

 12 costales, 8 lumbares, 3 sacrales and about 27 caudales. 



My warmest thanks to Prof, v. Siebold of the Munich 

 Museum, who was kind enough to send over for my in- 

 spection the beautiful stuffed type-specimens of Wagner's 

 Scitirus albipes (variics) and socialis. The nearer examina- 

 tion of these species beared for me a peculiar interest , 

 as neither Allen nor Alston were in the opportunity of 

 seeing them and therefore could not made out with accu- 

 racity to what species they belong or even if perhaps they 

 might stand as true species. 



Sciurus hudsonius. 



1778. Sciurus hudsonius Pallas. Nov. spec. Glirium. p. 376. 

 1877. Sciurus hudsonius Allen. Mon. N. Am. Rodentia. p. 672. 



Notes from the Leyden Museum, "Vol. V. 



