228 ' The American Naturalist. [ March, 
Creagrus contains a single species, and all the specimens the 
history of which is absolutely known were taken on Dalrymple 
Rock, near Chatham Island, a rock 65 feet high,—a most peculiar 
example of distribution of a single genus. 
The genus Nesomimus is represented by five species; one is 
peculiar to Charles, one to Hood, one to Albemarle, and one to 
Abingdon; the fifth, V. melanotis, is found on the central islands, 
Charles, Chatham, James, Indefatigable. 
Certhidea contains three species ; one is peculiar to Hood, one 
to Abingdon and Bindloe, and the third is again found in the 
central islands, Chatham, James, Indefatigable. 
Geospiza is represented by eleven species, two of which, G. 
dubia and nebulosa, are doubtful. Hood has a peculiar species, 
G. controstis Rigw. G. magnirostis has been found on Charles 
and Chatham; G. media, based on a single specimen, comes 
from Hood; G. strenua has been found on the central and 
northern islands; G. fortis, also G. fulginosa, are typical for the 
central islands; G. parvula and dentirostris seem to be the original 
inhabitants of Abingdon and Bindloe. 
Cactornis shows five species; C. drevirostis is only found on 
Chatham; C. assimilis is typical for Bindloe; C. abingdonii for 
Aiaia; C scandens and pallida spread over the central islands; 
no form has so far been found on Hood Island. 
Camarhynchus is represented by six species; none is known 
from Hood; two, C. prosthemelas and C. habeli, are characteristic of 
the northern Abingdon and Bindloe; C. townsendi has only been 
found on Charles; the other species occur on the central islands. 
As a whole we find in the birds the same distribution as in the 
reptiles, notwithstanding flight could enable them to reach the 
different islands. The northern islands, Abingdon and Albemarle, 
show different forms from the central islands. The same is the 
case with Hood, so far as it has been examined. Some species of the 
genus Geospiza, which contains the greatest members, have per- 
haps only lately spread over a greater number of islands than the 
others. This genus needs further examination. It seems that 
in the time when Darwin visited the islands the birds were more 
