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extend into the South Temperate zone, have six families, with one peculiar to them; while the Oriental region, which is wholly tropical, possesses the five cosmopolitan families only.
There are about 78 genera and 552 species of Anseres, giving 69 - species to a family, a high number compared with the Waders, and due to there being only one very small family, the Colymbidæ. The distribution of the Anseres, being more determined by temperature than by barriers, the great regions which are so well indicated by the genera and families of most other orders of birds, hardly limit these, except in the case of the genera of Anatidæ.
FAMILY 126.-STRUTHIONIDÆ. (2 Genera, 4 Species.)
The Ostriches consist of two genera, sometimes formed into distinct families. Struthio (2 sp.) inhabits the desert regions of North, East, and South Africa, as well as Arabia and Syria. It therefore just enters the Palæarctic region. Rhea (3 sp.) inhabits Temperate South America, from Patagonia to the confines of Brazil.
FAMILY 127.-CASUARIIDÆ. (2 Genera, 11 Species.
The Cassowaries and Emeus are confined to the Australian region. The Emeus, Dromæus (2 sp.), are found only on the
main-land of Australia (Plate XII, Vol. I. p. 441). Casuarius (9 sp.) inhabits the islands from Ceram to New Britain, with one species in North Australia; it is most abundant in the Papuan Islands.
FAMILY 128.—APTERYGIDÆ. (1 Genus, 4 Species.)
The species of Apteryx are entirely confined to the two larger islands of New Zealand. They are supposed to have some remote affinity with Ocydromus, a genus of Rails peculiar to Australia and New Zealand ; but they undoubtedly form one of the most remarkable groups of living birds (Plate XIII. Vol. I.
Struthious Birds recently extinct. A number of sub-fossil remains of birds, mostly large and some of gigantic size, having affinities to the Apteryx and, less closely, to the Cassowaries, have been discovered in New Zealand. These are all classed by Professor Owen in the genus Dinornis and family Dinornithidæ; but Dr. Haast, from the study of the rich collections in the Canterbury (New Zealand) Museum, is convinced that they belong to two distinct families and several genera. His arrangement is as follows. (See Ibis, 1874, p. 209).
FAMILY 129.—DINORNITHIDÆ. (2 Genera, 7 Species.)
Dinornis (5 sp.); Meionornis (2 sp.).
These had no hind toe, and include the largest species. Professor Newton thinks that they were absolutely wingless, being the only birds in which the fore limbs are entirely wanting..
FAMILY 130.—PALAPTERYGIDÆ. (2 Genera, 4 Species.)
Palapteryx (2 sp.); Euryapteryx (2 sp.).
Family 131.—ÆPYORNITHIDÆ. (1 Genus, 3 Species.)
A gigantic Struthious bird (Æpyornis), belonging to a distinct family, inhabited Madagascar.
It was first made known by its enormous eggs, eight times the bulk of those of the ostrich, which were found in a subfossil condition. Considerable portions of skeletons have since been discovered, showing that these huge birds formed an altogether peculiar family of the order.
General Remarks on the Distribution of the Struthiones. With the exception of the Ostrich, which has spread northward into the Palæarctic region, the Struthious birds, living and extinct, are confined to the Southern hemisphere, each continent having its peculiar forms. It is a remarkable fact that the two most nearly allied genera, Struthio and Rhea, should be found in Africa and South Temperate America respectively. Equally remarkable is the development of these large forms of wingless birds in Australia and the adjacent islands, and especially in New Zealand, where we have evidence which renders it probable that about 20 species recently coexisted. This points to the conclusion that New Zealand must, not long since, have formed a much more extensive land, and that the diminution of its area .by subsidence has been one of the causes--and perhaps the main one-in bringing about the extinction of many of the larger species of these wingless birds.
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.
THE DISTRIBUTION OF THE FAMILIES AND GENERA OF REPTILES
FAMILY 1.—TYPHLOPIDÆ.—(4 Genera, 70 Species.)
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 Palearctic 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.