SQUIRllELS, MAKMOTS. 359 



tinct groups — the flat-tailed forms (Sciuropterus), -which are abun- 

 dantly distributed over the northern parts of the North American 

 continent, and -whose range in Eurasia ertends from Lapland to 

 China and Java; and the round-tailed forms (Pteromj's), constitut- 

 ing a more so'atherly groujj, -whose home is the wooded districts of 

 tropical Southeast Asia, Japan, and some of the Malaysian islands. 

 By some authors the separation into two generic groups is not 

 recognised. The spermophiles or pouched marmots (Spermophilus) 

 and ground-squirrels (Tamias) are spread over the greater portion 

 of the temperate and boreal regions of the Northern Hemispliere, 

 but find their greatest numerical development in the New World. 

 The former, which in a measure connect the true marmots with 

 the squirrels, although sufficiently abundant in the far north of 

 Siberia and on the most elevated slopes of the Caucasus (S. musi- 

 cus), ai:)pear to be wanting in the Alps. The American species 

 occupy the western portion of the continent, ranging from the 

 Arctic seas to the plains of Mexico ; none are found east ot tlie 

 central plains or prairies. Of the ground-squirrels there are some 

 four or five recognised species, all of which are represented in North 

 America; the northern ground-squirrel or chipmunk (Tamias Asi- 

 aticus) is common to both the Eastern and "Western Hemispheres, 

 ranging in America from Lake Superior and Arizona to the Barren 

 Lands, and in Eurasia from Saghalien and Japan through Siberia 

 to the Dwina River. In the eastern portions of the American con- 

 tinent this species is replaced by the common chipmunk or striped 

 squirrel (Tamias striatus). 



The marmots (Arctomys) are restricted to the middle and north- 

 ern portions of the Northern Hemisphere, and comprise some ten 

 or more species, three of which are American. Of the last tho 

 best-known form is the woodchuck (A. monax), whose habitat ex- 

 tends from the Carolinas to the sixty-second parallel of latitude, 

 and from the Atlantic border to Minnesota. Of the two European 

 species the bobac (A. bobac) is more properly an Asiatic form, 

 ranging from Kamtchatka to the German frontier. The true mar- 

 mot, the Murmelthier of the Germans (A. marmota or Alpina), 

 inhabits the mountain-tracts of Southern Europe — Pyrenees, Alps, 

 Carpathians — between elevations of 5,000 and 10.000 feet. The 

 American "prairie" or "barking dogs," more properly marmots 

 (Cynomys), of which there are two species known, appear to be 



