166 kepokt— 1878. 



gascar, that by many zoologists it would most probably be considered a 

 variety only of the former species — a variety, it is quite conceivable, which 

 might result from separation in a comparatively very short period. 



The Malagasy subregion also possesses four other species of Pteropus 

 all very distinct from each other, having their nearest allies in the Aus- 

 tralian region. One of these species, Pt. rodricensis, recently described by 

 me, inhabits the small wind-swept island of Rodriguez, where its means of 

 subsistence must now be very limited. It is difficult to account for the 

 presence of such large and highly- organised species in these small islands, 

 except on the supposition that the islands were not only much larger at 

 some former time, but were also, as I have already remarked, closely 

 connected with a chain of slightly separated islands, uniting them with 

 the Indian and Australian continents. 



The Oriental region falls very slightly short of the Ethiopian in the 

 percentage of its peculiar species, and slightly exceeds it in genera. Of 

 110 species eighty-eight are peculiar ; of these eight only are also found in 

 the Ethiopian region, and they also extend into the Palsearctic. The 

 genera Cijnopterus,Eonycteris, Gcelops, and Cheiomeles are characteristic, but 

 the latter three are each represented by a single species only. Of the 

 remaining seventeen genera, two, Pteropus and Emballonura, are also com- 

 mon to the Malagasy subregion and to the Australian region, and ten are 

 also found in the Oriental and Australian regions. With the exception 

 of such cosmopolitan species as Miniopterus schreibersii and Vesperugo 

 abramus, the Oriental species extending into the Australian region appear 

 to inhabit only the adjacent parts of that region. The distinctiveness of 

 the Oriental and Australian Chiropterous faunas is well shown by a collec- 

 tion made lately in Duke of York Island and New Ireland, in which, 

 out of twelve species, two only are also known from the Oriental region. 



The Australian region comes next to the Neotropical in the number of 

 its peculiar genera ; of the twenty-one known, six are peculiar, and of these 

 four belong to the Pteropodidas, being nearly half the whole number of the 

 genera of that family. This region may therefore be considered the cradle 

 of the Megachiroptera, although the total number of all species falls far 

 short of either that of the Ethiopian or of the Oriental region, yet in the 

 percentage of peculiar forms it holds an intermediate place. 



Two of the Australian subregions, the Austro-Malayan and the New 

 Zealand, claim particular attention, the former for the great number of 

 its species, the latter for the opposite reason. Of sixty-four Australian 

 species, fifty-seven are peculiar, and of these nearly half appear to be limited 

 to the Austro-Malayan subregion ; while two species only, of which one is 

 peculiar, inhabit New Zealand. 



Great Britain, which nearly equals New Zealand in extent, has eight 

 times the number of its species ; and Madagascar, which is alone com- 

 parable with it in peculiarity of fauna, exceeds it almost in the same 

 proportion. 



The poverty of this subregion in species is, therefore, unequalled, and 

 undoubtedly depends to a great extent, if not altogether, on the com- 

 parative absence of insects, and probably especially of those species on 

 which bats prey. The peculiar structure of Mystacina tuberculata* appears 

 to indicate that this species seeks its food among the branches and leaves 

 of trees on which Longicorn Coleoptera, which are most abundant among 



* See my paper on this species in P. Z. S., 1876, p. 486. 



