AVES. 407 
fight. The long feathers attached to what may be termed the hand, gene- 
rally to the number of ten, are termed primaries ; the secondaries, variable 
in number, are those attached to the fore-arm; and the scapulars, are the 
smaller feathers, which are attached to the humerus. In describing birds, 
the term remiges is also used, to denote the feathers of the wings, which 
serve as oars; and rectrices, those of the tail, which have been considered 
to act asarudder. The smaller feathers, which cover the base of the wing 
and tail, are termed ¢ectrices. The anterior extremities, destined to support 
them in flight, can neither be used for prehension nor support, and birds 
thus take objects from the ground by their mouth. The neck is elongated, 
and the body thrown forward, that the bill may easily reach the ground. 
The pelvis is lengthened, to furnish an attachment for the muscles, which 
support the trunk upon the thighs; and there is an arrangement of muscles 
going from the pelvis to the toes, in such a manner that the weight of the 
animal bends the toes, and enables it to sleep perched upon one foot. 
The bony part of the tail is short, but it carries a row of strong feathers, 
which. spreading, contribute to support the bird. The number of these 
feathers is generally twelve, sometimes fourteen, and in the galline eigh- 
teen. The legs have a fermur, and a tibia, and the tarsus and metatarsus 
are represented by a single bone. ‘The toes are attached to the tarsus, and 
are generally three before and a kind of thumb behind; which, however, is 
sometimes wanting. In the swallow it is directed forwards. In the climb- 
ers, on the contrary, the external toe and thumb are directed backwards. 
The number of joints increases in each toe, counting from the thumb, which 
has two, to the external toe, which has five. Birds with toes entirely free, 
are adapted to walk or hop ona horizontal surface, such as the domestic 
fowl. Others with two toes behind and two before, such as the parrot, 
walk with difficulty, but climb with facility; and others again, such as 
ducks and swans, with the toes united by a membrane, are chiefly calculat- 
ed for motion in the water. The bill in birds is covered with a corneous 
substance, and as these animals swallow their food without mastication, 
they are not furnished with teeth. The upper mandible is formed chiefly 
of the intermaxillary bones, prolonged behind into two arches, of which the 
internal is composed of the palate bones, and the external of the maxillary 
and jugal bones; and this mandible is united to the cranium by elastic 
lamine. The bill is constructed less for bruising the food than for seizing 
and dividing it; and thus from the greater solidity and length of this organ, 
the nature of the food may be inferred. The bill, or beak, is sometimes 
furnished at its origin, with a fleshy or membranous caruncle, which is 
called the cere; and sometimes the beak is prolonged upon the forehead 
into a kind of horn or helmet, as in the calao. The two mandibles move- 
able upon one another, through the medium of an intermediate bone, placed 
at the articulation, is a distinguishing anatomical character, in the structure 
of the jaws of birds. The quills and feathers are composed of a bearded or 
