OF THE BEAVER AND OP SOME SQUIRRELS. 



1191 



matter of hair growth, accompanied in some cases by the suppres- 

 sion of one or both of the metatarsal pads. 



In the j^orth American Grey Squirrel (&'. (Neosciurus) caro- 

 linensis) the outer metatarsal pad is sometimes absent. When 



Text-fio-ure 49. 





A. Right hind foot of Sciurus carolinensis, with external metatarsal pad 



absent, in sunamer pelage (from dried skin). 



B. Right fore foot of the same, in winter pelage. 



C. „ hind foot of the same, in winter pelage, the external metatarsal 

 retained. 



D. Right hind foot of S. hypopyrrhus, or closelj' related species, in mid- 



winter pelage. 



retained it is a hemispherical tubercle set far forwards in front 

 of the inner, which is irregularly ovate and shorter than in 



79* 



