5*2 MAMMALIA. 



even a greater extent of surface than those of birds they consequently fly very 

 high, and with great rapidity. The thickness of their pectoral muscles is pro- 

 portioned to the motions they have to execute, and there is a ridge in the 

 middle of the sternum like that of Birds, to which they are attached. The 

 thumb is short and armed with a claw, by which they are enabled to creep and 

 to suspend themselves. Their hind feet are weak and divided into five toes, 

 almost of equal length, armed with trenchant and pointed nails. Their eyes 

 are excessively small, but their ears are frequently very large, and together 

 with the wings form a vast membranous surface, which is almost naked, and 

 so extremely sensible that it is probable they guide themselves through all the 

 sinuosities of their labyrinths, even after their eyes have been plucked out, 

 solely by the diversity of the impressions of the air. They are nocturnal, and 

 in our climate pass the winter in a stupor. During the day they suspend them- 

 selves in obscure places. They generally produce two young ones at a birth, 

 which cling to their mammae, and whose size is considerable in proportion to 

 that of the mother. This genus is very numerous, and offers many subdi- 

 visions. We must begin by separating from it the 



PTEROPUS, Brisson. 



Trenchant incisors in each jaw, and grinders with flat crowns, the food, 

 consequently, consists chiefly of fruit, of which it destroys considerable quan- 

 tities; it also successfully pursues birds and small quadrupeds. It is the 

 largest Bat known, and the flesh is eaten. The membrane is deeply notched 

 between the legs ; it has hardly any tail ; the index finger is but half the 'ength 

 of the medius, and has a third phalanx, and a little nail, which is wanting on 

 the other bats ; the muzzle is simple, the nostrils are widely separated, the ears 

 of a middling size, and the tongue is bristled with points that curve backwards. 

 It inhabits the East Indies. 



They have never been found out of the south of Asia or the Indian Archi- 

 pelago. 



a. Without tails, and four incisors in eachjnn-. 



P. edulis, Geoff. (The Black Rousette.) Blackish brown, deepest beneath, 

 wings nearly four feet from tip to tip. From the Moluccas and the Straits of 

 Sunda, where they are found in great numbers during the day suspended to the 

 trees. Two other species, P. vu/garis, and the P. nthecolles, Geoff", inhabit 

 the Mauritius. 



b. With a small tail and four incisors in eachjau: 



M.Geoffroy was the first who described this species of this subdivision. 

 One of them grey and woolly, Pier. JEgypticus, is found in the caves of 

 Egypt. 



The Pteropi being taken away, we have the true BATS left, which are all 

 insectivorous, and have three grinders on each side in each jaw, bristled with 

 conical points, they are preceded by a variable number of false molars. Their 

 index never has a nail, and, one subgenus excepted, the membrane is always 

 extended between the two legs. 



