678 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XIII, 
peculiar genera of Antelopes and of some other types; amongst birds by the 
occurrence of Pterocletes (sand grouse), Phcenicopteri (flamingces), Otidide 
(bustards) and Cursoriine ; amongst reptiles by the possession of the families 
Eublepharidx, Chameleontide, and Uropeltide, together with many peculiar 
Geckonide, Agamide, and Lacertid, and amongst batrachians by about one- 
half of the genera found in each sub-region being absent in the other, The 
difference between the reptiles and batrachians by itself would justify the 
classification of the two areas as distinct regions, a view adopted by several 
writers, 
The following figures show the total number of genera recorded from the 
Cisgangetic sub-region and the percentage of them not ranging into the 
Transgangetic area, the Himalayas and Burma :— 
Cisgangetic. Not Transgangetic. 
Mammals seo....sees 62 14 or 22°5 per cent, 
Birds gi... sparina 20656 346 47 or 13 sa 
Reptiles ............ bos eo 39 or 42 és 
Batrachians ...... eae ald 9 or 53 ei 
Freshwater fishes... 958 9 or 155 
dy 
Omitting bats, the number of Cisgangetic mammalian genera is forty-six, 
of which 14 or 30 per cent. are wanting in the Himalayas and east of the 
Bay of Bengali. 
The difference between the Cisgangetic vertebrate fauna and that ihevinae 
the rest of the Indo-Malay or Oriental region is partly due to the absence in 
the former of numerous Eastern types, and partly to the presence of two con- 
stituents besides the Oriental genera, which, especially in forest, form a major- 
ity of the animals present. One of these two constituents consists of mam- 
mals, birds, and reptiles having a distinct relationship with Ethiopian and 
Holarctic genera, and with the Pliocene Siwalik fauna. This constituent of 
the Cisgangetic fauna it is proposed to distinguish by the term Aryan. The 
other constituent is composed of reptiles and batrachians, and may be termed 
the Pravidian element, The latter is well developed in the south of the 
Peninsula, and especially along the south-west or Malabar Coast and in Ceylon, 
but it gradually disappears to the northward, its northern limit, so far as is 
known at present, not extending to the 20th parallel of north latitude, 
It is probable that this is the oldest part of the Cisgangetic fauna, 
and it may have inhabited the country since India was connected by 
land with Madagascar and South Africa, across what is now the Indian 
Ocean, in Mesozoic and early Cenozoic times. The other two elements, 
the Indo-Malay or Oriental and the Aryan, are probably later immigrants, 
and its wider diffusion may indicate that the Oriental element has inhabited 
the Indian Peninsula longer than the Aryan has, There appears some reason 
for regarding the Oriental portion of the fauna as dating in India from Mio- 
cene times and the Aryan from Pliocene, whilst in the Pleistocene. epoch the 
proportion of Aryan to Oriental types of mammals in India, as shown by the 
