24 
ISLAND LIFE. 
[part i, 
area completely separated from the others. The most northerly 
is C. tricar unculatus of Costa Rica and Veragua, a brown bird with 
a white head and three long caruncles growing upwards at the 
base of the beak. Next comes C variegatus , in Venezuela, a 
white bird with a brown head and numerous caruncles on the 
throat, perhaps conterminous with the last; in Guiana, ex- 
tending to near the mouth of the Rio Negro, we have C. niveus, 
the bell-bird described by Waterton, which is pure white, with 
a single long fleshy caruncle at the base of the beak ; the last 
species , C. nudicollis, inhabits South-east Brazil, and is also 
white, but with black stripes over the eyes, and with a naked 
throat. These birds are about the size of thrushes and are all 
remarkable for their loud-ringing notes like a bell or a blow on 
an anvil, as well as for their peculiar colours. They are there- 
fore known to the native Indians wherever they exist, and we 
may be the more sure that they do not spread over the inter- 
vening areas where they have never been found, and where the 
natives know nothing of them. 
A good example of isolated species of a group nearer home, 
is afforded by the snow-partridges of the genus Tetraogallus. 
One species inhabits the Caucasus range and nowhere else, 
keeping to the higher slopes from 6,000 to 11,000 feet above the 
sea, and accompaning the ibex in its wanderings, as both feed 
on the same plants. Another has a wider range in Asia Minor 
and Persia from the Taurus mountains to the South-east corner 
of the Caspian Sea ; a third species inhabits the Western Hima- 
layas, between the forests and perpetual snow, extending east- 
wards to Nepal, while a fourth is found on the north side of the 
mountains in Thibet, and the ranges of these two perhaps over- 
lap ; the last species inhabit the Altai mountains, and like the 
two first appears to be completely separated from all its allies. 
There are some few still more extraordinary cases in which 
the species of one genus are separated in remote continents or 
islands. The most striking of these is that of the tapirs, forming 
the genus Tapirus, of which there are two or three species in 
South America, and one very distinct species in Malacca and 
Borneo, separated by nearly half the circumference of the globe. 
Another example among quadrupeds is a peculiar genus of moles 
