RODENTIA. 



81 



more scantily supplied with hairs than that of the European Squirrel; the ears 

 are smooth, and the skin brown, with five black stripes and two white ones. 



We ought also, most probably, to distinguish the Guerlinguets, a species 

 with a long, and almost round tail. They are found in both continents. 



The following have been separated already. 



PTEROMYS*, 



Or the Flying Squirrels, to which the skin of the flank, extending between 

 the fore and hind legs, imparts the faculty of supporting themselves for a 

 moment in the air, and of making very great leaps. They have long bony 

 appendages to their feet, which support a part of this lateral membrane. 



There is a species found in Poland, Russia, and Siberia. (Sc. Volans, 

 Lin.) The Flying Squirrel, about the size of a rat, grey ash-coloured above, 

 white underneath. It lives solitarily in the forests. Another species, 



Sc. voluccellu, Lin. (The American Flying Squirrel.) Is reddish-grey above; 

 white beneath ; size less than that of the preceding ; tail three-fourths as long 

 as the body. It lives in troops in the prairies of North America. S. 

 petaurista, Lin. (the Taguau) is found in the Indian Archipelago ; it is 

 nearly the size of a cat; the male has a fine lively marone above, and red 

 underneath ; the female is brown above, and whitish underneath. 



M. Geoffroy has very properly separated from this genus the 



CHEIRO.MVSf, 



Or the Aye- Ayes, whose inferior incisors, much more compressed, and, above 

 all, more extended from front to back, resemble ploughshares. Each foot has 

 five toes, of which four of the anterior are excessively elongated, the medius 

 being more slender than the others ; in the hind feet the thumb is opposable to 

 the other toes ; so that they are in this respect among the Rodentia what the 

 opossums are among the Carnaria. The structure of their head is otherwise 

 very different from that of the other Rodentia, and is related to the Quadru- 

 mana in more points than one. 



There is only one species of the Aye-Aye known. It was discovered at 

 Madagascar by Sonnerat. It is the Cheir. madagascariensis. (The Aye- 

 Aye.) Size of a hare, of a brown colour, mixed with yellow; tail long and 

 thick, with stout black bristles; ears large and naked. It is a nocturnal 

 animal, to which motion seems painful ; it burrows under ground, and uses its 

 slender toe to convey food to its mouth. 



Linnaeus and Pallas united in one single group, under the name of Mus, 

 all the Rodentia furnished with clavicles which they could not distinguish by 

 some very sensible external character, such as the tail of the squirrel or that 

 of the beaver, from which resulted the utter impossibility of assigning to them 



* Pteromys, Winged Rat. -f- Cheir omys, a. Rat with band*. 



