676 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol, X11. 
Another element of interest lies in the fact that the peninsula of India isa 
land of great geological antiquity, there keing no evidence that it has ever 
been submerged, although the greater part of the Himalayas and Burma 
have at times been beneath the sea, " 
The plan adopted for the study has been to divide the whole country into 
nineteen tracts, distinguished by physical characters—such as rainfall, tem- 
perature, presence or absence of forests, and prevalence of hilly ground, and 
to construct tables showing the distribution of each genus of land or fresh 
water vertebrate in the tracts. Genera have been selected for consideration 
because families and sub-families are too few im number and too wide in 
range, whilst species are too numerous and too unequal in importance, It is 
recognised that there is much difference in the value of genera in different 
groups, the generic differences in passerine birds, for instance, being as 
a rule of inferior rank to those in some other orders of birds, or to 
those generally adopted amongst mammals, reptiles,and batrachians, In 
the demarcation of regions and sub-regions, terrestrial mammalia are regarded 
as of primary importance. 
The tracts are the following :— ; 
A, Indo-Gangetic Plain. 
1. Punjab, Sind, Baluchistan, and Western Rajputana. 
. Gangetic Plain from Delhi to Rajmahal. 
3. Bengal from Rajmahal to the Assam Hills, 
B. Indian Peninsula. 
4. Rajputana and Central India as far south as the Nerbudda, 
5, Deccan from the Nerbudda to about 16° N, lat. and from the Western 
Ghats to long. 80° E. 
6. Behar, Orissa; &c., from the Gangetic Plain to the Kistna. 
7. Carnatic and Madras, south of 5 and 6, and east of the Western Ghats. 
8. Malabar Coast, Concan, and Western Ghats or Sahyadri range from 
the Tapti River to Cape Comorin. 
C. Ceylon. 
9. Northern and Eastern Ceylon. 
10. Hill Ceylon, the Central, Western, and Southern Provinces. 
D. Himalayas. 
11. Western Tibet and the Himalayas above forest. 
12, Western Himalayas from Hazara to the western frontier of Nepal. 
13, Eastern Himalayas, Nepal, Sikhim, Bhutan, &c. File ge’ 
EE, Assam and Burma. 
14, Assam and the hill ranges to the south, with Manipur and Arrakan, 
15. Upper Burma, north of about 19° N, lat. 
16 Pegu from the Arrakan Yoma to the hill ranges east of the Sittang, 
17. Tenasserim as far south as the neighbourhood of Mergui. 
18. South Tenasserim, south of about 13° N, lat. 
19. Andaman and Nicobar Islands, 
