VERTEBRATA: MAMMALIA. 763 



pal only, in other cases with two short phalanges in addition. It is usu- 

 ally clawless, but may (as in most of the Pteropidce) be unguiculate. Of 

 the remaining digits the medius is the longest ; and all are clawless, and 

 possess two or three phalanges. 



In the hind-limb, the fibula is mostly incomplete, and the foot is fur- 

 nished with five clawed toes. To the os calcis is attached, in most Bats, a 

 cartilaginous or bony process or spur, which is directed inwards along the 

 lower margin of the inter-femoral membrane, and serves to put this upon 

 the stretch during flight. 



The Bats are all crepuscular and nocturnal in their habits, 

 and are sometimes carnivorous, sometimes frugivorous. The 

 eyes are small, but the ears are very large, and their sense of 

 touch is most acute. During the day they retire to caves or 

 crevices amongst the rocks, where they suspend themselves by 

 means of the hind -feet, which are provided with curved 

 claws. In their flight, though they can fly in the genuine and 

 proper sense of the term, and can turn with great ease, they 

 are by no means as rapid and as active as are the true birds. 

 The tail is sometimes short, sometimes moderately long, and 

 is usually included in a continuation of the leathery patagium, 

 which stretches between the hind-legs, and is termed the 

 " inter-femoral membrane." The body is covered with hair, 

 but the patagium is usually hairless, or nearly so. Most of 

 the Bats hibernate. 



The Cheiroptera are conveniently divided into the two sec- 

 tions of the Insedivora and Frugivora, according as the diet 

 consists of insects or of fruits. 



SECTION A. INSECTIVORA (Microcheiroptera). In this section 

 are the four families of the Vespertilionidce, RhinolophidcB, 

 Noctilionidcz, and Phyllostomida. 



Fam. i. VespertilionidcE. In this family are the ordinary 

 Bats, distinguished by having a dentition very like that of the 

 order of the Insectivorous Mammals, the molar teeth being 

 furnished with small pointed eminences or cusps, adapted for 

 crushing insects, and the incisors being of small size. The 

 nose is not furnished with leaf-like appendages, and the tail is 

 elongated, and enclosed in a large inter-femoral membrane. 

 The species of this family are generally distributed over the 

 temperate and warm regions of both the Old and New Worlds. 

 About fifteen species of this family have been described as 

 British, but of these only two are at all common. Of these 

 two, the Pipistrelle ( Vespertilio pipistrelld} is the commonest 

 species, occurring over the whole of Britain. The long-eared 

 Bat (Plecotus auritus] is also not uncommon, and is distin- 

 guished by its greatly elongated ears, which are confluent 

 above the forehead. The largest British species is the Noctule 



