XV HAMSTERS AND COTTON RATS 479 



hordes so familiar (as far as their description is concerned) to 

 everybody. The Lemmings do not return from their exodus. 

 They die from various causes, including combats with one 

 another. Their chief foes, however, are A\'olves and Gluttons, 

 Buzzards and Eavens, Owls and Skuas, which batten on the 

 migrant hordes. Their sudden increase in numbers recalls the 

 similar increase at times of the Field-Vole, to which reference 

 has already been made. 



Ellohius is an Old-^A'orld genus, which leads a " Talpine " life, 

 and has in consequence rudimentary external ears and veiy 

 small eyes. The tail is short. Contrary to what might be 

 expected from its mode of life, the claws upon the digits are 

 not strong. 



The remaining genera of Vole-like Murines are Phenacomys 

 and Sytuqitomys from North America, and Siphneus from I'alae- 

 arctic Asia. Ecotomys is one of those genera which are common 

 to both the Palaearctic and the Nearctic regions, but the bulk of 

 the species are Xorth American. 



Sub-Fam. 9. Sigmodontinae. — This is the name given to 

 another sub-family of Murine liodents, a group which includes 

 the Hamsters in the Old World as well as a large number of 

 South American genera of Eat-like animals. Of these latter 

 there are a very large number, the bulk of the group being 

 American. 



The Hamsters, genus C'ricetus, as it is usually called, although 

 apparently the correct name is Hmnster, are Old- World forms of 

 Pouched Eats. The Common Hamster, C. frnmentarius, is about 

 210 mm. long, with a tail of 58 mm. It has cheek pouclies. 

 The small and the large intestines are not very unequal in 

 length, and the caecum is fairly large, being about one-sixth to 

 one-seventh of the length of either. It is a purely vegetable- 

 feeding creature, and in Germany where it occurs (and from 

 which language its vernacular name is derived), hibernates during 

 the winter in its burrow, having previously surrounded itself 

 with a great accumulation of food carried thither. 



To North America are peculiar the genera Onychomys, Sig- 

 modon, and Feromyscus. The genus Sir/7nodon, the Cotton Eats, 

 reaches Central America, and even gets a little farther south. 

 The other two genera, though mainly North American, also 

 extend their range to the south. Onychomys has hairy foot- 



