SQUIRRELS. 31 



Suborders contains by far the greatest number of species, and is 

 itself divisible into three sections, of which the Squirrel, Rat, and 

 Porcupine are severally typical. 



Of the Sciuromorpha, or Squirrel section, may be mentioned the 

 following : 



The Scaly-tailed Flying Squirrels (Anomalurus) of Equatorial 

 Africa (Case 27, above) , with membranous parachutes like the Flying "Case 27.] 

 Lemurs described above (p. 30), and with a series of pointed scales 

 so placed under the base of their tails as to be of use when the 

 animal is resting on a vertical tree-trunk, the points of the scales 

 sticking into the surface of the bark. 



The true Flying Squirrels of Southern Asia (Pteromys), perhaps 

 the most brightly coloured of all Mammals ; with the exception of 

 their flying membrane, there is no structural difference between 

 them and the ordinary Squirrels. 



The Chipmunks, Sousliks, and Marmots (Tamias, Spermophilus, 

 an&Arctomys) (Case 28, above) live in burrows of their own construc- 

 tion. The Common Marmot (Arctomysmarmotta] inhabits the Alpine 

 regions of Europe. The North-American Prairie-Marmots (Cy- 

 nomys), better known as Prairie-Dogs, excavate a large number 

 of deep burrows close together, forming what is called a town. 

 Frequently they have to share their home with weasels, burrowing 

 owls, and rattlesnakes, which quarter themselves on the unfortunate 

 Marmots, and feed on their young. 



The Squirrels (Sciurus) (Case 28, below) form the largest genus of [Case 28.] 

 the present group, about 70 species being known, distributed over 

 the whole world with the exception of the Australian region. They 

 range in size from species more than a foot in length, such as 

 the Purple Squirrel (Sciurus indicus) of India, down to others 

 scarcely larger than Mice, as, for example, the Black-eared Squirrel 

 of Borneo (S. melanotis). Squirrels are generally bright-coloured, 

 and vary in an extraordinary degree, as may be gathered from an 

 examination of the instructive series of S. hypopyrrhus, the Grizzled 

 Squirrel, placed in the lower part of Case 28. This species is orna- 

 mented with patches or bands of white, yellow, grey, brown, and 

 black, in every combination, each variety passing, by insensible 

 gradations, into the next. Specimens of our common Squirrel also 

 (S. vulgaris), killed respectively in England, Switzerland, and 



