BATS 251 



its ordinary summer haunts as the Bermudas, where Mr. J. M. Jones states that it 

 is observed occasionally at dusk during the autumn months hawking about accord- 

 ing to its nature in search of insects ; but as it is never seen except at that particular 

 season, it is clear that it is not a resident, but merely blown across the ocean 

 by those violent northwest gales which also usually bring numbers of birds from 

 the American continent. The hoary bat is, however, not the only species in which 

 there is evidence of periodical migrations. Thus Dr. Merriam tells us that the 

 silver-haired bat ( Vesperugo noctivagans) > which ranges as far north as Hudson's 

 Bay, is known to visit every spring and autumn a solitary lighthouse situated on a 

 solitary rock off the coast of Maine, fifteen miles from the nearest island and thirty 

 miles from the mainland. This rock being uninhabited permanently by bats, 

 the occurrence of these stray individuals in the spring and fall seems to afford 

 perfectly conclusive evidence of the migratory habits of the particular species to 

 which they belong. 



In regard to their geographical distribution, it may be observed that 

 bats are found over almost the whole world ; one species at least even 

 extending as far northward as the Arctic circle. They are far more abundant 

 within the tropics and the warmer parts of the temperate zones than elsewhere ; and 

 it is to those regions alone that the larger species are restricted. Indeed, the bats, 

 according to Mr. Wallace, may be regarded as some of the most characteristic of the 

 Mammals of the tropical zone, occupying in this respect a position second only to 

 that held by the apes, monkeys, and lemurs, and becoming suddenly much less 

 plentiful, both as regards the number of individuals and of species, when we pass 

 into the temperate zone, and still more reduced in both respects when we reach the 

 colder parts of those regions. 



In some instances particular family groups of bats are confined more or less ex- 

 clusively to particular regions of the earth's surface ; although others enjoy an 

 almost world-wide distribution. For instance, while the fruit-bats are entirely con- 

 fined to the warmer regions of the Old World, and the vampires and their allies to 

 America, some of the more common types of ordinary European bats, like Vesperugo 

 and Vespertilio, are almost cosmopolitan. It will be found that these cosmopolitan 

 forms belong to the more generalized types, while those restricted to particular dis- 

 tricts are usually the more specialized form. It is somewhat curious that, according 

 to Dr. Dobson, bats are quite unknown in Iceland, St. Helena, Kerguelen, and the 

 Galapagos islands. 



The number of species of bats known to science is now enormous. 

 In a list published in 1878, Dr. Dobson recognized no less than four 

 hundred distinct species, arranged in eighty genera, and six families. Since that 

 date the number has, however, been so largely increased, that we shall probably be 

 not far wrong in setting it down as but little, if at all, short of four hundred and 

 fifty. With such a portentous list to deal with, it will be obvious that, in"a work 

 like the present, all that can be attempted is to indicate some of the more generally 

 interesting and leading types, leaving the others for technical treatises. The old 

 English name Flittermouse, by which these animals were known to our ancestors, 

 and by which they are still designated in certain parts of the country, conveys a 



