The Mammalia have not been collected with sufficient completeness in both
islands to make a general comparison of much value, and so many species have
been obtained only as live specimens in captivity, that their locality has often
been erroneously given, the island in which they were obtained being substituted
for that from which they originally came. Taking into consideration only those
whose distribution is more accurately known, we learn that Sumatra is, in a
zoological sense, more nearly related to Borneo than it is to Java. The great man-
like apes, the elephant, the tapir, and the Malay bear, are all common to the two
former countries, while they are absent from the latter. Of the three long-tailed
monkeys (Semnopithecus) inhabiting Sumatra, one extends into Borneo, but the
two species of Java are both peculiar to it. So also the great Malay deer (Rusa
equina), and the small Tragulus kanchil, are common to Sumatra and Borneo,
but do not extend into Java, where they are replaced by Tragulas javanicus. The
tiger, it is true, is found in Sumatra and Java, but not in Borneo. But as this
animal is known to swim well, it may have found its way across the Straits of
Sunda, or it may have inhabited Java before it was separated from the mainland,
and from some unknown cause have ceased to exist in Borneo.
In Ornithology there is a little uncertainty owing to the birds of Java and
Sumatra being much better known than those of Borneo; but the ancient
separation of Java as an island is well exhibited by the large number of its
species which are not found in any of the other islands. It possesses no less than
seven pigeons peculiar to itself, while Sumatra has only one. Of its two parrots
one extends into Borneo, but neither into Sumatra. Of the fifteen species of
woodpeckers inhabiting Sumatra only four reach Java, while eight of them are
found in Borneo and twelve in the Malay peninsula. The two Trogons found in
Java are peculiar to it, while of those inhabiting Sumatra at least two extend to
Malacca and one to Borneo. There are a very large number of birds, such as the
great Argus pheasant, the fire-backed and ocellated pheasants, the crested
partridge (Rollulus coronatus), the small Malacca parrot (Psittinus incertus), the
great helmeted hornbill (Buceroturus galeatus), the pheasant ground-cuckoo
(Carpococcyx radiatus), the rose-crested bee-eater (Nyctiornis amicta), the great
gaper (Corydon sumatranus), and the green-crested gaper (Calyptomena viridis),
and many others, which are common to Malacca, Sumatra, and Borneo, but are
entirely absent from Java. On the other hand we have the peacock, the green
jungle cock, two blue ground thrushes (Arrenga cyanea and Myophonus
flavirostris), the fine pink-headed dove (Ptilonopus porphyreus), three broad-
tailed ground pigeons (Macropygia), and many other interesting birds, which are
found nowhere in the Archipelago out of Java.