The borders of the subregion to the northeast and northwest are undefined, since in those areas no insurmountable barriers exist fcr animals. Therefore, considerable mixing with fauna of the Paleo-Arctic occurs. On the one hand, northern (Holarctic) forms enter the territory of the Indian-Indochinese subregion; on the other hand, certain Indian forms are found in the far qorth. In the northeastern area of the Indian-Indochinese subregion certain species of mole families are encountered that are alien to the region as a whole; and in the northwest there are rodents of the subfamily Gerbillinae and Asiatic wild asses. Tibetan—that is, Holarctic—fauna is distributed in the north throughout high-altitude areas of the Himalayas.
V. G. GEPTNER