SCIURUS FOSSOR. 93 



The number of upper premolars seems to be very in- 

 constant in this species, as I find some specimens with 

 two and others with one : perhaps the first small one is 

 often deciduous as Allen believes. 



Hab. The greater part of the North-American continent , 

 extending northward to the limit of forest vegetation and 

 southward over the uorthern-two-thirds of the United 

 States (Allen 1. c. p. 684) , perhaps to Honduras (see 

 infra). 



Mounted specimens in the Ley den Museum: 



1. Adult male , Vancouver-Island , Forrer. — 2. Half 

 grown individual, Labrador, Möschler , 1863. — 3. Female, 

 North- America , Beske, 1824. — 4 and 5. Halfgrown spe- 

 cimens , North- America. — 6 and 7. Adult specimens , Ca- 

 lifornia, Dodds Valley, Gruber, 18G6. — 8. Halfgrown, 

 Mexico. — 9 and 10. Males, Honduras, Frank, 1873. — 11 

 and 12. Young specimens, locality unknown. 



13. Skull of N». 1. — 14. Skull of N^ 4. — 15. Skull 

 of N*^. 6. — 16. Skull of N". 9, lower jaws wanting. — 

 17. Skull of N«. 10. 



Nos. 1, 2, 3, 4, 5, 8 and 9 agree in color with typical 

 ^MC?som'Ms-specimens ; 6 and 7 with douglassi-iax. ; 10 , 11 

 and 12 with richardsoni-Yar. 



SciuTus fossor. 



1848. Sciurus fossor Peale. Mammals and Birds. U. S. Ex. 



Exp. p. .55. 

 1877. Sciurus fossor Allen. Mon. N,-Amer. Rodentia. 



p. 731. 



This very easily recognizable species constantly shows 

 two upper premolars, the first one being well-developed. 



Hab. Oregon and California. 



Notes from tlie Leyden IMuseum, Vol. "V. 



