346 ZOOLOGICAL GEOGRAPHY. [PART III. 
The foregoing list, although small, contains an assemblage of 
species which are wholly Oriental in character, and several of 
which (Tarsius, Galeopithecus, Tupaia) are characteristic’ and 
highly peculiar Malayan forms. At the same time these islands 
are completely separated from the rest of Malaya by the total 
absence of Semnopithecus, Hylobates, Felis, Helarctos, Rhinoceros, 
Manis, and other groups constantly found in the great Indo- 
Malay islands and peninsula of Malacca. We find apparently 
two sets of animals: a more ancient series, represented by the 
deer, Galeopithecus, and squirrel, in which the species are distinct 
from any others; and a more recent series, represented by 
Macacus cynomolgus, and Viverra tangalunga, identical with 
common Malayan animals. The former indicate the earliest 
period when these volcanic islands were connected with some 
part of the Malayan sub-region, and they show that this was 
not geologically remote, since no peculiar generic types have 
been preserved or differentiated. The latter may indicate either 
the termination of the period of union, or merely the effects of 
introduction by man. ‘The reason why a larger number of 
mammalian forms were not introduced and established, was 
probably because the union was effected only with some small 
islands, and from these communicated to other parts of the 
archipelago; or it may well be that later subsidences extin- 
guished some of the forms that had established themselves. 
Birds of the Philippine Islands.—These have been carefully 
investigated by Viscount Walden, in a paper read before the 
Zoological Society of London in 1873, and we are thus furnished 
with ample information on the relations of this important 
portion of the fauna. 
The total number of birds known to inhabit the Philippines 
is 219, of which 106 are peculiar. If, however, following our 
usual plan, we take only the land-birds, we find the numbers 
to be 159 species, of which 100 are peculiar ; an unusually large 
proportion for a group of islands so comparatively near to 
various parts of the Oriental and Australian regions. The 
families of birds which are more especially characteristic of the 
Indo-Malay sub-region are about 28 in number, and examples 
