The wide distribution of the Struthiones may, as we have already suggested (Vol. I., p. 287.), be best explained, by supposing them to represent a very ancient type of bird, developed at a time when the more specialized carnivorous mammalia had not come into existence, and preserved only in those areas which were long free from the incursions of such dangerous enemies. The discovery of Struthious remains in Europe in the Lower Eocene only, supports this view; for at this time carnivora were few and of generalized type, and had probably not acquired sufficient speed and activity to enable them to exterminate powerful and quick-running terrestrial birds. It is, however, at a much more remote epoch that we may expect to find the remains of the earlier forms of this group; while these Eocene birds may perhaps represent that ancestral wide-spread type which, when isolated in remoter continents and islands, became modified into the American and African ostriches, the Emeus and Cassowaries of Australia, the Dinornis and Æpyornis of New Zealand.

CHAPTER XIX.

THE DISTRIBUTION OF THE FAMILIES AND GENERA OF REPTILES AND AMPHIBIA.

REPTILIA.

Order I.—OPHIDIA.

Family 1.—TYPHLOPIDÆ.—(4 Genera, 70 Species.)

General Distribution.
Neotropical
Sub-regions.		Nearctic
Sub-regions.		Palæarctic
Sub-regions.		Ethiopian
Sub-regions.		Oriental
Sub-regions.		Australian
Sub-regions.
— 2. 3. 4— — — —— 2 — 41. 2. 3. 41. 2. 3. 41. 2 — —

The Typhlopidæ, or Blind Burrowing Snakes, are widely scattered over the warmer regions of the earth, but are most abundant in the Oriental and Australian regions, and least so in the Neotropical. They are absent from the Nearctic region; and in the Palæarctic are found only in South-eastern Europe and Japan.

The most extensive genus is Typhlops, comprising over 60 species, and having a range almost as extensive as the entire family. The other well characterised genera are:—

Typhlina (1 sp.), ranging from Penang to Java and Hong Kong; Typhline (1 sp.), the Cape of Good Hope; Dibamus (1 sp.), New Guinea.