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Rh the exception of the Arctic regions; and seventeen of these have been recognised as inhabiting the British Islands. They are distributed in two Families, Pteropidæ and Vespertilionidæ. This Family, though small in the number of its genera and species, contains the largest of all the Bats; some of them exceeding five feet in expanse of wing. They have cutting incisors in each jaw, and tuberculated molars, the crowns of which are longitudinally grooved. They are thus fitted for subsistence on fruits. The wings are somewhat rounded; the interfemoral membrane and the tail are always small, sometimes wanting. The thumb is large, the fore-finger short, sometimes nailed, possessing three phalanges, or joints, while the rest have but two. The head is long and pointed; the muzzle has no appendages, nor the ear a tragus.

The species, which are sometimes called Roussettes, are found in the islands of the Indian Ocean and the surrounding coasts, in Japan, Madagascar, and South and West Africa.

These Bats are often known by the name of Vampyre Bats, though the distinctive term Vampyrus is now applied to a genus of another Family. They are without any tail, and the interfemoral membrane is very scanty: the teeth are inc. $2—2⁄2—2$; can. $1—1⁄1—1$; mol. $5—5⁄5—5$;=32. Upwards of twenty species of this genus are known, chiefly