450 



VEHTEBRATA. 



The Michigan Mouse, M. Michiganensis^ is, above, light grayish-brown; below, of a whitish 

 color. Its length is four inches. 



These and some other American species in California, and other frontier parts of the United 

 states, are arranged by Baird under several generic heads. 



The Wood Rat, or Cottox Rat, arranged by Say and Ord under the generic name of Sigmo- 

 don, and to which they give the specific title of hispidum — the Arvicola hispidus ofGodman — is 

 six inches long, with a tail four inches; above it is yellowish-brown ; beneath, ash-color. It is 

 \cr\ abundant in the Southern States, where it prefers hedges, ditches, and deserted fields to gar- 

 dens and cultivated land"-; it feeds on seeds, grass, and vegetables, but relishes flesh, and readily 

 devours birds thai fall wounded in the fields; it also eats crayfish which it gets from the ditches. 

 It is very voracious, attacks and devours other species of mice and rats, also killing and eating its 

 own species. It is exceedingly prolific, lives in burrows, and is nocturnal in its habits. This, like 

 many other species of mice, forms the staple food of foxes, wild-eats, owls, hawks, and other flesh- 

 eaters. 



DENDROMYS TYPICUS. 



We now turn to various species of rat-like animals, but of genera distinct from the preceding. 



The Genus DENDROMYS : Dendromys, includes two African species, the D. typicus and D. 

 melanotis, which are the size of common mice, and are of a pearly-gray color, and have a black 

 band running along the back. 



Genus ACOMYS : Acomys. — Of this there are several African species. The Cairo Moubb, 

 A. Cahirinus, is mentioned by Aristotle, and is of the size of a common mouse; the fur is spiny, 

 and of an ash-color on the back ; below it is softer, and of a lighter shade. It is found in Syria. 

 The A. spinosissimus is found in Mozambique. 



Genus CRICETOMYS : Cricctomys. — There is only one well known species of this genus, the 

 C. Gambianus. It is larger than the brown rat, and has cheek-pouches; it burrows in the earth, 

 but climbs trees to obtain fruits, on which it feeds. It is found in Fernando Po and Kordofan. 

 M. Rappel calls it the Goliath Rat. Species of Cricetomys are also found in Mozambique. 



Genus SACCOSTOMYS : Saccostomys. — Of this there are two species, S. lapidarius and <S". 

 fuscus ; they are distinguished by cheek-pouches. 



Genus PELOMYS: Pelomys. — Of this there is one species, P. fa liar, having the incisors 

 furrowed like those of the Gerbils. The two preceding genera are of Mozambique. 



Genus STEATOMYS : Steatomys. — Of this there are two species, the S. edulis and S. Knbsii. 

 having incisors resembling those of the preceding, but with short tails. These are African. There 



