66 
ZOOLOGICAL GEOGRAPHY. 
[part iit. 
ductiveness, but this is, no doubt, partly due to our knowledge 
of Cuba and Jamaica being much more complete than of 
Hayti. The species of resident land-birds at present known are 
as follows : — 
Cuba 68 species of which 40 are peculiar to it. 
Hayti 40 „ 17 „ „ 
Jamaica 67 „ „ 41 „ „ 
Portorico 40 „ „ 15 „ „ 
Lesser Antilles 45 „ „ 24 „ „ 
If we count the peculiar genera of each island, and reckon 
as (§) when a genus is common to two islands only, the 
numbers are as follows : — Cuba 7J, Hayti 3J, Jamaica 8J, 
Portorico 1, Lesser Antilles 3J. These figures show us, that 
although Jamaica is one of the smaller and the most isolated of 
the four chief islands, it yet stands in the first rank, both for the 
number of its species and of its peculiar forms of birds, — and 
although this superiority may be in part due to its having been 
more investigated, it is probably not wholly so, since Cuba has also 
been well explored. This fact indicates, that the West Indian 
islands have undergone great changes, and that they were not 
peopled by immigration from surrounding countries while in 
the condition we now see them ; for in that case the smaller 
and more remote islands would be very much poorer, while 
Cuba, which is not only the largest, but nearest to the mainland 
in two directions, would be immensely richer, just as it really 
is in migratory birds. 
The number of birds common to the four larger islands is 
very small — probably not more than half a dozen ; between 20 
and 30 are common to some two of the islands (counting the 
Lesser Antilles as one island) and a few to three ; but the great 
mass of the species (at least 140) are confined each to some one 
of the five islands or groups we have indicated. This is an amount 
of isolation and speciality, probably not to be equalled else- 
where, and which must have required a remarkable series of 
physical changes to bring about. What those changes probably 
were, we shall be in a better position to consider when we have 
completed our survey of. the various classes of land animals. 
