94 



THE PROSIMIANS. 



head downwards by the hind feet, and 

 enveloped in their patagium as in a mantle. 

 They live indeed socially, but not in such 

 large companies as the flying-foxes. They 

 awaken at dusk and begin clambering about 

 in the trees in search of their food, which 

 consists largely of insects, larvae, eggs, and 

 small animals, but partly also perhaps of juicy 

 fruits and leaves. They cannot exactly fly; 

 but the patagium serves as a sort of parachute, 

 with the aid of which they are able to make 

 astonishing leaps from one tree to another. 

 The ordinary colugo (Galeopithecus volitans) 

 is represented in fig. 36. Whether several 

 species can be distinguished is still doubtful. 

 They inhabit the large Sunda Islands and 

 extend as far as the Philippines, and are met 

 with also on the mainland, especially in Siam 

 and Cochin-China. They are, however, com- 

 paratively rare and not often observed. 



GEOGRAPHICAL DISTRIBUTION AND 

 DESCENT OF THE PROSIMIANS. 



The geographical distribution, as well as 

 the origin of the Prosimii, present some 

 extremely interesting problems, which indeed 

 have not yet been completely solved. 



All the Prosimii now living belong ex- 

 clusively to the tropical and subtropical parts 

 of the Old World, and indeed to three 

 separate regions, which are sharply marked 

 off from one another, having no genera nor 

 even families in common. The East Indies 

 and especially the Sunda Islands form the 

 home of the loris, tarsiers, and flying-lemurs; 

 West Africa is inhabited by the potto and 

 angwantibo, the whole of Africa by the 

 galagos; all the others, that is to say, all the 

 numerous forms of indris and true lemurs, as 

 well as the aye-aye, are confined to Mada- 

 gascar. 



This distribution may be held to point first 

 of all to the fact, that Madagascar forms a 

 zoological province altogether distinct from 



the continents, showing a greater amount of 

 peculiarity than many now isolated regions, 

 a peculiarity which, moreover, must date from 

 the earlier Tertiary times, since it is likewise 

 manifested in relation to other mammals. 

 But further, one cannot help recognizing that 

 the very varied forms of Prosimii must belong 

 to several separate stocks which have been 

 distinguished from one another since the 

 beginning of the Tertiary period. The East 

 Indian and West African types cannot be 

 derived from the same stock as those of 

 Madagascar, and all speculations as to the 

 former existence of a continent, now largely 

 submerged, but which, when it did exist, ex- 

 tended from the East Indies to Madagascar 

 and the mainland of Africa, perhaps even to 

 America, having the large East African island 

 as its centre, — all speculations about this so- 

 called Lemuria, from which the Prosimii, and 

 then, as their descendants, the monkeys and 

 the human race were supposed to have been 

 distributed over the earth, at once fall to the 

 ground, in face of the simple fact that the 

 various types of the locally separate Prosimii 

 can only by violence be united into one 

 group. 



Till a few years ago no fossil Prosimii 

 were known; but recently their remains have 

 been found in the Upper Eocene of France 

 (Quercy), and in considerable numbers in 

 the Lower Eocene of Wyoming in North 

 America. But here we must probably dis- 

 tinguish two sets of discoveries. 



The sole incontestable European prosimian 

 has been found in the phosphorites of Quercy 

 in Western France. It is so closely allied to 

 the West African potto by the structure of 

 its head and teeth that it can scarcely be held 

 to form a separate genus. The African 

 centre accordingly then lay more to the north. 

 To this form, of which we possess the entire 

 skull, the name of Necrolemur has been 

 given. 



But in addition to this, there have been 

 found in the gypsum of Montmartre and in 



