INTRODUCTION. 
sxxvii 
before, and two behind : while the Swift and the Goatsucker, by a parti- 
cular conformation of the foot, are enabled to place their four toes forward. 
The Ostrich alone has but two. Some of the species have long legs and long 
necks, as the Heron ; others, as the Swan and the Goose, possess legs of or- 
dinary length, with necks of immoderate extension; and others have extremely 
short legs, in proportion to the size of their bodies, as the Goatsucker and 
the Cuckoo : and those which have long legs, have invariably long necks, 
to enable them to gather their food. The feet of most birds are so placed, 
as to preserve the body in equilibrium ; but in the Grebes and the Divers, 
they are situated so as to enable them to swim with facility ; but so far are 
they from the centre of gravity, that they walk on land with extreme 
awkwardness and labour. The toes in most birds are quite divided, though 
in a few they are partly connected by a small membrane, as in birds of the 
poultry kind ; while in others, as in the Nightjar and Ringplover, the inner 
and middle toes are united by a slight membrane, extending nearly to the 
first joint. In the red-necked Grebe, they are furnished with wide, oval 
membranes ; but in the grey Phalarope and Coot, they are narrow and 
scalloped. The membrane that margins the toes of the Waterhen, the 
Rail, and the Water-rail, is thin and narrow, merely skirting them ; but, 
on the other hand, the three fore toes, of the Goose and Duck kinds, are 
united, even to their extremities, by a full web. In the Shag, the Pelican, 
the Gannet, the Divers, and the Cormorant, their four toes are connected 
together by a similar web. The claws or nails of birds are sometimes 
slender and sharp, as in the Sparrow kinds ; broad, obtuse, and blunt, as 
in the Divers ; strong, sharp-pointed, and edged, as in the talons of 
Eagles and Flawks ; serrated, as in the Goatsucker, Cormorant, and 
Heron ; straight and slender, as in the hind toe of the Lark ; short 
and w'eak, with a small cavity on the inner side, as in the Cuckoo ; 
long and curved, as in the Titlark. In birds that seek their food on 
the waters, they are commonly small, blunt, and obtuse ; in those that 
seat themselves on the branches of trees, long and crooked ; in those that 
principally live on the ground, almost straight ; and in those that require 
