Representatives of the order Ophidia are found over the whole world, with the exception of Iceland, Ireland, and New Zealand, between the Northern limit of 67° in Europe (_Vipera berus_), 60° in Asia (_Vipera berus_), and 52° in America (_Tropidonotus ordinatus_), and the Southern limit of 44° (_Philodryas schotti_). The highest altitudes reached by them are 14,000 feet in the Himalayas (_Tropidonotus baileyi_), 9,700 feet in the Alps (_Vipera aspis_), and 9,000 feet in the Andes (_Liophis albiventris_). They are most numerous between the tropics, and the number of species gradually diminishes to the North and South. For the purpose of showing the distribution of the principal groups, we will follow the divisions into families and subfamilies enumerated above (p. 4). _Typhlopidæ._--S.E. Europe, S. Asia, Africa, Australia (exclusive of Tasmania), C. and S. America, and W. Indies. _Glauconiidæ._--S. Asia (as far E. as Sind), Africa (exclusive of Madagascar), C. America (extending into the S. parts of N. America), S. America. _Pythoninæ._--S. Asia, Africa (exclusive of Madagascar), Australia (exclusive of Tasmania), C. America. _Boinæ._--S.E. Europe, C. and S. Asia, N. Africa, Madagascar, Mauritius, W. Polynesia, S.W. of N. America, C. and S. America, and W. Indies. _Ilysiidæ._--S.E. Asia, S. America. _Uropeltidæ._--India and Ceylon. _Xenopeltidæ._--S.E. Asia. _Acrochordinæ._--S.E. Asia, C. America. _Colubrinæ._--The whole range of Ophidia, except Tasmania. _Dasypeltinæ._--Africa (exclusive of Madagascar). _Homalopsinæ._--S.E. Asia, N. Australia. _Dipsadomorphinæ._--S. Europe, C. and S. Asia, Africa, Australia (exclusive of Tasmania), C. America (extending into the S. parts of N. America), S. America. _Elachistodontinæ._--India. _Hydrophiinæ._--Indian and Pacific Oceans. _Elapinæ._--S. Asia, Africa (exclusive of Madagascar), Australia and Tasmania, Fiji Islands, C. America (extending into the S. parts of N. America), S. America. _Amblycephalidæ._--S.E. Asia, C. and S. America. _Viperinæ._--Europe, Asia, Africa (exclusive of Madagascar). _Crotalinæ._--S.E. Europe, Asia, America.