1891.] The Origin of the Avifauna of the Bahamas. 539 
where seven endemic genera are found. Perhaps in distinctness 
from related species the avifauna may be compared with that of 
Grand Cayman, an island situated 175 miles south of Cuba, and 
200 miles northwest of Jamaica, The character of the formation 
of this island I do not know; Commander Bartlett has said of it, 
with Little Cayman and Misteriosa Bank, that they are the sum- 
mits, fast appearing above tide-mark, of a submarine range having 
an average height of nearly 20,000 feet. 
Through Mr. Cory’s collectors and the naturalists of the “Alba- 
tross ? Grand Cayman has been thoroughly explored, and fifteen 
endemic species and subspecies have been found there. These 
are largely derived from Cuban birds, and eleven of them are gen- 
erically represented in the Bahamas. 
From this review of Bahaman bird life we may presume to offer 
the following conclusions: . 
First—The Bahamas are largely West Indian in their affini- 
ties, and the group of islands may claim the rank of a fauna of the 
Antillean region, characterized by the presence of forms differ- 
entiated from their West Indian ancestry and by the infusion of 
a slight Floridan element. 
Second.—A greater number of endemic species have been 
derived from Cuba than from any other region. 
Third —North American migrant species which breed in higher 
latitudes, while occurring in great numbers in the Bahamas, at 
certain seasons of the year, have-not assisted in forming the resi- 
dent avifauna. 
- Fourth —The avifauna is of comparatively recent origin. 
fifth —Forms of a common ancestor may be differentiated from 
this ancestor in much the same manner, and thus, though having 
widely separated habitats, more closely resemble each other than 
they do the parent species. : 
Sixth—In several instances certain Bahaman forms inhabiting 
_ Contiguous islands have become differentiated from each other 
without, so far as we can observe, being subjected to thanged 
climatic or physiographic conditions. 
Seventh—We may, perhaps, assume from this that these birds 
originally owe their characters to individual variations which, 
among a number of individuals, have become permanent. 
