THE PRAIRIE MARMOTS 1255 



more specialized genus of Rodents, which may be designated prairie marmots, 

 although they are often most inappropriately termed prairie dogs, while they are 

 likewise known as barking squirrels. In size these animals hold a position inter- 

 mediate between the susliks and the true marmots. They have small ears, and gen- 

 erally short tails, while their cheek pouches are much less capacious than those of 

 the susliks. In their fore-feet the first toe is well developed and furnished with a 

 claw nearly as large as that of the fifth. The skull is massive, with the large post- 

 orbital processes directed nearly outward (as shown in the figure on p. 1239); and 



THE PRAIRIE MARMOT. 



(One-fourth natural size. ) 



the molar teeth are very stout, with three grooves on their grinding surfaces, in place 

 of the two characterizing those of the other two genera of the group. A further 

 peculiarity in connection with the upper molar teeth is that the two series, in place 

 of running nearly parallel, are convergent behind. 



There are three species of prairie marmots, two of which are confined to the 

 prairies of the Rocky mountain plateau, while the third inhabits Mexico. The 

 common prairie marmot ( Cynomys ludovicianus] is confined to the drier districts to 

 the east of the Rocky mountains and is entirely an inhabitant of open plains. 

 The length of the head and body usually varies from eleven and one-half to twelve 



