THE CHIPMUNK OK (JROIIND SQUIRREL. 



471 



cncli sido of the U|)i)oi' jnw; chocks with i)ouchos that ()|)c?i Ix'twooii 

 tlic teeth and lips. 



The six or seven forms belonging to this genus are all geo- 

 graphical I'aees of a siiiiilc spe('i(\s limited lo North America east 

 of the Kocky ]\Iountains. These animals are commonly known as 

 ground squirrels, but that name is also applied to a number of 

 related genera, differing chiefly in number of teeth. The name 

 chipmunk is generally restricted to the squirrels of this genus and 

 is, therefore, the more desirable name to adopt. 



TAMIAS STRIATUS (Linnaoiis). 

 CHIPMUNK; GROUND SQUIRREL. 



Sciiirns striatus Linn., Syst. Nat., ed. 10, Vol. 1, p. 64, 1758. 

 Tamias striatus Baird, 11th Rep. Smiths. Inst., p. 55, 1857. 

 Evermann and Butler, Proc. Ind. Acad. Sci. for 1893, pp. 129. 

 Sciurus striatus lysteri McAtee, Proc. Biol. Soc. Wash., Vol. 20, 

 p. 3, 1907. 



Diagnostic characters. — Easily distinguished by its general 

 brown color with five stripes of black and two of light color on 

 the back. 



Description. — The chipmunk is too w^ell known to require an 

 elaborate description. The head is brown with a blackish stripe 

 running from the side of the nose through the eye and back to the 

 ear. This is bordered above by a white stripe and that is followed 

 by another narrow, indistinct stripe of blackish. Under the eye 

 there is also a white stripe running from the base of the ear to the 

 cheek. There is another dark but indistinct stripe below this. 



The back has a median blackish stripe running from the occiput 

 to the rump. On each side of this are two pairs of alternating pale 

 and dark stripes, the lower light stripe being nearly white, while 

 the median pair are grizzled brown. The rump is bright rufous 

 chestnut and the side and shoulder grizzled yellowish brown with 

 some black tipped hairs; tail grizzled black and gray above and 

 chestnut below. 



Measurements. — Specimens from northern Indiana measure 239 

 mm. 9 9/16 in.) in total length; tail, 95mm. (3 12/16 in.); hind 

 foot, 30mm. (1 3/16 in.). 



Skull and teeth. — The skull (fig. 5) is slender and tapers grad- 

 ually from the zygomatic arches to the tip of the nasals, the outlines 

 being much less square than in Sciimis hudsonicus, which has a 

 skull of about the same length but broader. The upper cheek teeth 

 are but four in number. 



