OHAP. XVIII.] 
BIRDS. 
337 
found in the Andaman and Nicobar Islands ; in the Philippines, 
Gilolo, and the smaller Papuan Islands, and in Japan ; yet not in 
any of the large Malay Islands or in Australia. The other genus, 
Calmnas, consists of but a single species, yet this ranges from the 
Nicobar Islands to New Guinea. It is not, however, as far as 
known, found on any of the large islands, but seems to prefer 
the smaller islands which surround them. We here have the 
general preference of pigeons for islands, further developed in 
these two genera into a preference for small islands ; and it is 
probable that the same cause — the greater freedom from danger — 
has produced both phenomena. 
Of the geological antiquity of the Columbse we have no evi- 
dence ; but their wide distribution, their varied forms, and their 
great isolation, all point to an origin, at least as far back as that 
we have assigned as probable in the case of the Parrots. 
Order V.—GALIINM. 
Family 86 .— PTEKOCLID^E. (2 Genera, 16 Species.) 
General Distribution. 
Neotropical 
Sub-regions. 
Neakctic 
S UB-EEGIONS. 
PaL/EARCTIC 
Sub-regions. 
Ethiopian 
Sub-regions, 
Oriental 
Sub-regions. 
Australian 
Sub-regions. 

— 
- 2 . 3.4 
1 - 3.4 
1 
The Pteroclidae, or Sand-grouse, are elegantly formed birds with 
pointed tails, and plumage of beautifully varied protective tints, 
characteristic of the Ethiopian region and Central Asia, though 
extending into Southern Europe and Hindostan. Being pre- 
eminently desert-birds, they avoid the forest-districts of all these 
countries, but abound in the most arid situations and on the 
most open and barren plains. The distribution of the genera is 
as follows : — 
Pterocles (14 sp.), has the same range as the family ; Syrrhap- 
tes (2 sp.), normally inhabits Tartary, Thibet, and Mongolia to 
the country around Pekin, and occasionally visits Eastern Europe. 
But a few years back (1863) great numbers suddenly appeared in 
VOL t II. Z 
