VOL. XXXVIII.] PHILOSOPHICAL TRANSACTIONS. SSQ 



another in Grew's museum of the Royal Society, under the name of flying 

 squirrel, which Dr. Grew takes to be the animal which Scaliger, in Exercit. 

 217, § 9, describes under the name of felis volans. Lawson, in his history 

 of Carolina, exhibits a third. And Gesner de quadruped, p. 743, a fourth, 

 which he calls mus ponticus or scythicus, or sciurus volans and alatus. 



Fig. 1, 3, 4, pi. 15, represent the one M. Klein had. It is less than the 

 common squirrel, but larger than the field mouse; its skin is very soft, ele- 

 gantly adorned with grey and dark grey pile; it has large, prominent, black, 

 and very beautiful eyes; small ears and very sharp teeth; most of them are 

 mischievous; but M. Klein's was not much so; it would not catch at the finger 

 though put to its mouth : but it could not be trusted if provoked. When it 

 does not leap, its tail lies close to its back; but when it does, it hangs it down, 

 moving from side to side. It eats bread, baked without salt; but the fresh tops 

 of birch are its .favourite food; it cares not for nuts or almonds; it makes its 

 bed in an elegant manner of the moss of the birch, and with surprising facility 

 drawing it with its feet, lies buried in it, and does not stir from thence in the 

 day-time unless disturbed, or pressed with thirst. The skin of its flying instru- 

 ment may be expanded from its sides like a sail for nearly the breadth of a palm ; 

 it adheres to the bending of the hinder feet, but is connected to a bony articu- 

 lation with the fore feet ; at the extremity of this articulation the skin is downy. 

 When it sits quiet, or moves with its natural pace, this articulation, which is 

 parallel with its feet, cannot be distinguished; but as soon as it leaps, it is 

 moved, and forms a right angle with the fore foot; whence the skin is expanded, 

 though likewise a strong panniculus carnosus, that passes under the whole skin, 

 much assists its leaping. From this M. Klein gathers, that this little animal 

 does not properly fly, but that it can leap to places at some distance, with 

 greater ease than other animals of the same kind, and by means of its sails 

 continue longer in the air. With this flying squirrel compare the vespertilio 

 admirabilis Bontii in Hist. Nat. et Med. Ind. Orient, cap. 16, Apud Pison. 

 p. 68. Piso himself would doubt, whether it is to be classed among the family 

 of bats. 



On considering the size and form of the vespertilio admirabilis M. Klein 

 could not satisfy himself of the truth of what Bontius asserts, namely, that 

 they fly in flocks, like wild geese; but he rather thinks, that such animals 

 come nearer to the nature of flying squirrels, and that they use their sails in 

 the same manner; notwithstanding what Bontius asserts, that about the evening 

 they are observed pendulous in the air, or from trees; but that rather it may 

 hence be proved, that these vespertiliones, as well as the flying squirrels, sleep 

 in the day-time, and about the evening quit their retreats, leap from one tree 



