228 
Mr. Blytb/s Commentary 
the bulk of Dr. Jerdon’s volumes. To a very great extent, and 
indeed essentially, the sub-Himalayan fauna, up to the zone of 
Conifer (2 , is an extension westward of that of the Indo-Chinese 
subregion, as contrasted with the fauna of India proper; and the 
same more eastern fauna, in its low-country forms, extends also 
to the Bengal Sundarbans and along the tarai or marshy tract 
at the foot of the northern hills. A very marked change becomes 
apparent on quitting the alluvium of the lower Ganges in a 
westerly direction, where sundry species common to the Indian 
peninsula with Ceylon at once present themselves abundantly 
which never stray into Lower Bengal, while not a few of the 
more characteristic species of Lower Bengal and of the Indo- 
Chinese countries disappear as suddenly and entirely. 
In the higher ranges of the sub-Himalayas the Indo-Chinese 
and more tropical forms give way, for the most part, to those 
characteristic of the temperate parts of Europe and Asia; and 
the Fringillidce , in particular, become very numerous in species, 
which, southward of the Himalaya, are replaced by Plocei and 
Estreldina , one species only (Carpodacus erythrinus, besides 
Emberizince) extending far into the plains as an ordinary winter 
visitant. The connexion of the avifauna of the Himalaya with 
that of the plains is indeed chiefly maintained by species which 
resort to the hills to breed and return to pass the winter south¬ 
ward, insessorial birds being chiefly here referred to. 
The proper Indian fauna, as distinct from the sub-Himalayan, 
culminates in the hills of Southern India and especially of Cey¬ 
lon ; but a few peculiar species are elsewhere scattered within 
the area of that particular fauna, as notably the remarkable 
Tree-creeper, Salpoimis spilonotus (akin to the Australian form 
Climacteris) , in the jungles of Behar, and the Courser-like 
wader, Rhinoptilus bitorquatus (with a sole African congener), in 
Northern Coromandel. The great plains of Upper India are repro¬ 
duced in the tableland of the Dukhun, where again are charac¬ 
teristic species (common to both) which have not been observed 
elsewhere; such are Hirundo concolor, Pericrocotus erytliropygius, 
and Malacocercus malcolmi. But though subordinate provinces 
are more or less traceable, as indicated by Dr. Jerdon in his 
Introduction (xxxix et seq.), the most prominent distinction is 
