_Special Relations of the Javan Fauna to that of the Asiatic Continent._--These relations are indicated by comparatively few examples, but they are very clear and of great importance. Among mammalia, the genus Helictis is found in Java but in no other Malay country, though it inhabits also North India; while two species, _Rhinoceros javanicus_ and _Lepus kurgosa_, are natives of Indo-Chinese countries and Java, but not of typical Malaya. In birds there are five genera or sub-genera--Zoothera, Notodela, Crypsirhina, Allotrius, and Cochoa, which inhabit Java, the Himalayas, and Indo-China, all but the last extending south to Tenasserim, but none of them occurring in Malacca, Sumatra, or Borneo. There are also two species of birds--a trogon (_Harpactes oreskios_), and the Javanese peacock (_Pavo muticus_), which inhabit only Java and the Indo-Chinese countries, the former reaching Tenasserim and the latter Perak in the Malay Peninsula. Here, then, we find a series of remarkable similarities between Java and the Asiatic continent, quite independent of the typical Malay countries--Borneo, Sumatra, and the Malay Peninsula, which latter have evidently formed one connected land, and thus appear to preclude any independent union of Java and Siam. The great difficulty in explaining these facts is, that all the required changes of sea and land must have occurred within the period of existing species of mammalia. Sumatra, Borneo, and Malacca have, as we have seen, a great similarity as regards their species of mammals and birds, while Java, though it differs from them in so curious a manner, has no greater degree of speciality, since its species, when not Malayan, are almost all North Indian or Siamese. There is, however, one consideration which may help us over this difficulty. It seems highly probable that in the equatorial regions species have changed less rapidly than in the north temperate zone, on account of the equality and stability of the equatorial climate. We have seen, in Chapter X., how important an agent in producing extinction and modification of species must have been the repeated changes from cold to warm, and from warm to cold {385} conditions, with the migrations and crowding together that must have been their necessary consequence. But in the lowlands, near the equator, these changes would be very little if at all felt, and thus one great cause of specific modification would be wanting. Let us now see whether we can sketch out a series of not improbable changes which may have brought about the existing relations of Java and Borneo to the continent.