This rapid sketch of the principal facts of Ophidian distribution suffices to show how difficult it would be to frame geographical regions that would give expression to these facts. Such regions would necessarily be very different from those adopted in dealing with the distribution of the other divisions of the class Reptilia. This is a task which need not be attempted on the present occasion. A few words as to the salient characters of the European fauna, which is a poor one as compared with other parts of the world. The single species of the genera _Typhlops_ and _Eryx_ must be regarded as outposts from South-Western Asia; the single species of _Ancistrodon_, which extends from Central Asia into a very small territory to the south-east, is also an Asiatic type. The genera _Tropidonotus_, _Zamenis_, _Coluber_, _Coronella_, and _Contia_, are characteristic of the Northern Hemisphere, and the first three are, besides, equally well represented in the Oriental region; a few species of _Tropidonotus_ are also found in Africa and Madagascar. _Coelopeltis_, _Macroprotodon_, and _Tarbophis_ are the northern outposts of an Afro-Indian group, although, with the exception of the third, exclusively confined to the circum-Mediterranean district. The genus _Vipera_ is also represented in East Africa and in Southern Asia, but the species _V. berus_ is essentially a northern type, extending to the highest latitude reached by any snake, and ranging all over Northern Asia to the Amur and Sachalien. The same species reaches the greatest altitude at which any snake has been observed on the northern side of the Alps--viz., 9,000 feet. Of the twenty-eight species inhabiting Europe, only two are generally distributed: _Tropidonotus natrix_ and _Coronella austriaca_. One is to be regarded as a northern form, although occurring locally in the south: _Vipera berus_. It is the reverse with _Coluber longissimus_. The others may be described as southern forms, two only as ranging from west to east: _Zamenis gemonensis_ and _Coelopeltis monspessulana_; one of more central habitat: _Vipera ursinii_. The remainder may be divided into two groups--those of more western, and those of more eastern distribution. To the first group belong _Tropidonotus viperinus_, _Zamenis hippocrepis_, _Coluber scalaris_, _Coronella girondica_, _Macroprotodon cucullatus_, _Vipera aspis_ and _Vipera latastii_; to the second, _Typhlops vermicularis_, _Eryx jaculus_, _Tropidonotus tessellatus_, _Zamenis dahlii_, _Coluber quatuorlineatus_, _dione_, _leopardinus_, _Contia modesta_, _Tarbophis fallax_ and _iberus_, _Vipera renardi_, _ammodytes_, _lebetina_, and _Ancistrodon halys_.