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.
The Tortricidæ, or Short-tailed Burrowing Snakes, are a small family, one portion of which ranges from India to Cambodja, and through the Malay islands as far as Celebes and Timor; these form the genus Cylindrophis. Another portion inhabits America, and consists of:—
Charina (1 sp.), found in California and British Columbia; and Tortrix (1 sp.), in Tropical America.
We have here a case of discontinuous distribution, indicating, either very imperfect knowledge of the group, or that it is the remnant of a once extensive family, on the road to extinction.
The curious nocturnal carnivorous Snake, forming the genus Xenopeltis, and the sole representative of this family, ranges from Penang to Cambodja, and through the Malay Islands to Celebes.
The Uropeltidæ, or Rough-tailed Burrowing Snakes, are strictly confined to Ceylon and the adjacent parts of Southern India, and would almost alone serve to mark out our second Oriental sub-region. The genera are:—
Rhinophis (7 sp.), Ceylon; Uropeltis (1 sp.), Ceylon; Silybura (8 sp.), Anamally Hills and Neilgherries; Plecturus (3 sp.), Neilgherries and Madras; and Melanophidium (1 sp.), the Wynand.
The Calamariidæ, or Dwarf Ground Snakes, are found in all warm parts of the globe, extending north into the United States as far as British Columbia and Lake Superior; but they are absent from the Palæarctic region, with the exception of a species found in Persia. The species are in a very confused state. The best characterised genera are the following:—
Calamaria (20 sp.), Persia, India to Java and the Philippine Islands, Celebes, and New Guinea; Rhabdosoma (18 sp.), Mexico and South America, and also the Malay Islands as far east as Amboyna, Timor, and New Guinea; Typhlocalamus (1 sp.), Borneo; Macrocalamus (1 sp.), India; Aspidura (3 sp.), India and Ceylon; Haplocerus (1 sp.), Ceylon; Streptophorus (3 sp.), Central and South America;—with a host of others of less importance or ill-defined.
The Oligodontidæ are a small family of Ground Snakes which have been separated from the Calamariidæ, and, with the exception of a few species, are confined to the Oriental region. The best characterised genera are:—
Oligodon (12 sp.), India, Ceylon, and Philippines; and, Simotes (24 sp.), India to China and Borneo. In addition to these, Achalinus is founded on a single species from Japan; and Teleolepis consists of three species from North and South America.
The Colubrine Snakes are universally distributed over the globe, and they reach the extreme northern limits of the order. They are, however, almost absent from Australia, being there represented only by a few species of Tropidonotus and Coronella in the northern and eastern districts. This great family consists of four divisions or sub-families: the Coronellinæ (20 genera, 100 species), the Colubrinæ (16 genera, 70 species), the Dryadinæ (7 genera, 50 species), and the Natricinæ (7 genera, 50 species). The more important genera of Colubridæ are the following:—
Ablabes, Coronella, Ptyas, Coluber, and Tropidonotus—all have a very wide distribution, but the two last are absent from South America, although Tropidonotus reaches Guatemala; Tomodon, Xenodon, Liopis, Stenorhina, Erythrolampus, Elapochrus, Callirhinus, Enophrys, and Dromicus—are confined to the Neotropical region; Hypsirhynchus, Cryptodacus, Jaltris, and Coloragia, are confined to the West Indian Islands; Chilomeniscus, Conophis, Pituophis, and Ischnognathus, to North America, the latter going as far south as Guatemala; Compsosoma, Zamenis, Zaocys, Atretium, Xenochrophys, and Herpetoreas, are peculiarly Oriental, but Zamenis extends into South Europe; Lytorhynchus, Rhamnophis, Herpetethiops and Grayia, are Ethiopian; Rhinechis is peculiar to Europe; Megablabes to Celebes, and Styporhynchus to Gilolo; Cyclophis, is found in the Oriental region, Japan, and North America; Spilotes, in the Nearctic and Neotropical regions; Xenelaphis in the Oriental, Ethiopian, and Palæarctic regions; Philodryas, Heterodon and Herpetodryas in America and Madagascar, the latter genus being also found in China.