169 
Three different zones of elevation are very clearly indicated, less 
by the appearance of forms similar to, or identical with, those of the 
subtropical and temperate regions (as is the case in the flora and 
in several other parts of the fauna), than by the appearance of new 
species and genera peculiar and confined to the Himalaya, and espe- 
cially by the disappearance* of such species which are abundant in 
the lowlands. The most common species of Lizards in the plains 
south of the Himalaya are Calotes versicolor and Tiliqua rufescens. 
Both ascend the mountains ; but the former disappears at an eleva- 
tion of 3400 feet, the other at 9600 feet. The most common species 
of Snakes throughout the Indian continent are Tropidonotus quin- 
cunciatus and Simotes russellii: they disappear at 4000 feet, whilst 
Clothonia johnii, by no means a rare species, extends nearly to 
10,000 feet+. With regard to the Batrachians, we find that Bufo 
melanostictus, the most common East Indian Toad, disappears at 
9000 feet in the Southern Himalaya; whilst Bufo vulgaris, the most 
common Toad of the Palearctic region, extends to 10,200 feet in 
Tibet. Thus, although we must always bear in mind this fact— 
that changes in the faunas of the various elevations succeed each 
other gradually, and that these successions necessarily vary at differ- 
ent localities even of the same elevation—we may well suggest that 
at an elevation of 4000 feet, and again of 10,000 feet, such a change 
takes place, that we are justified in separating the Amphibio-fauna 
of the Himalayas into three divisions, concurring thus with the views 
of Mr. Hodgson, who has established the same zones for the Mam- 
mals and Birds f. 
1. The Tropical Zone ; zone of Tropidonotus quincunciatus (from 
the level of the plains to 4000 feet above the level of the sea). 
The climate of this zone bears an entirely tropical character ; it is 
covered by a very rich vegetation §, with the prevalent timber gigantic 
and scaled by climbing Leguminose ; bamboo and luxuriant ferns 
abound, and the first decided signs of a change of the flora cannot be 
observed below 3500 feet. In accordance with this, the Amphibio- 
fauna is extremely similar to that of Tropical India; we find in this 
zone the following species || :— 
* The upper elevational limits of the land-animals are much more distinct than 
the lower ones ; vice versd in sea-animals. See Schmarda, ‘Geograph. Verbreit. 
der Thiere,’ p. 70 
t The black variety of the Copra de Capello (Naja tripudians) certainly ascends 
higher than 8000 feet ; it would very finely illustrate our division if this sug- 
gestion should prove to be true. 
t Journ. As. Soc. Beng. 1850, p. 772. 
§ The botanical characters of the zones are taken from Dr. Hooker’s ‘ Himalaya 
Journal.’ 
|| In all the following enumerations of species, those only have been referred to, 
the elevational limits of which have been stated. 
