Passekes. BIRDS. Passeres. 273 
the foot which exhibits a granular or reticulated 
appearance, is the lower surface of the toes. The toes 
are not furnished at the base with a distinct membrane 
or small web, such as is usually found at this point in 
other birds ; but, on the other hand, the outer toe of 
each foot is generally united to the middle one for a 
greater or less extent ; sometimes only at the base, but 
sometimes nearly to the extremity. The' claws with 
which the toes are armed are either of moderate length 
and strength, or very long and slender; they never 
emulate the formidable talons of the predaceous birds, 
nor do they degenerate into the flat scratching nails 
characteristic of the gallinaceous birds. 
This structure of the hind limbs renders the Passeres 
very active on their feet, whether they disport them- 
selves amongst the branches and twigs of the trees, or 
hop, as is their usual manner of progression, on the 
ground. Their wings or anterior members are also 
well developed, and they generally possess the power 
of flight in a very high degree of perfection. In this 
respect, indeed, we find a considerable variety amongst 
the members of this group, some of them furnishing 
most remarkable examples of rapid and long-continued 
flight ; others enjo}dng the power of moving through the 
air with more moderation, but few deserving the char- 
acter of being feeble flutterers. In accordance with these 
variations in the volitant power, the form of the wings 
also varies, being long and pointed in those which fly 
best, and broader and rounded at the tip in proportion 
as the power of flight diminishes ; but the number of 
primary quill feathers in the wings is tolerably uniform, 
being generally ten, although the first of these is fre- 
quently very small, or even altogether wanting. The 
quill feathers of the tail are generally twelve in number. 
The form of the bill, as may be supposed from 
the statement already made with regard to the great 
difference of food, is very variable ; but it is to be 
remarked that it never partakes of the strongly-hooked 
character which prevails in the preceding order, nor is 
its base covered by anything like a cere. The bill is 
ordinarily conical; sometimes short and stout; some- 
times elongated and slender; in many of the long-billed 
forms, the whole of the organ is more or less curved ; 
and a considerable number of those with short bills 
have the upper mandible slightly arched, and bent 
dovTi at the tip, near which the margins are armed 
with small teeth. The object of these various forms of 
the bill, and of others to which we need not refer here, 
will be readily seen when we come to treat of the his- 
tory of the species belonging to this order, in the classi- 
fication of which they are also of great importance. 
"With regard to the internal structure of these birds, 
we need only state that the oesophagus is dilated into 
a small crop ; that the walls of the stomach are very 
thick and muscular, forming a gizzard; and that in many 
01 them the mferior larynx, situated at the point of imion 
of the two bronchial tubes coming from the two sepa- 
rate lungs, is provided with a complicated apparatus of 
small muscles, by the action of which the birds are 
enabled to modulate their notes in a surprising manner, 
so as to produce that delightful music which charms 
the ears of all wanderers in the country throughout the 
spring and summer. 
From the vast variety of forms included in this order, 
and the gradual manner in which their distinctive char- 
acters blend one with the other, the division of these 
birds into subordinate groups presents no small diffi- 
culties ; and the opinions of authors upon their classifi- 
cation are almost as various as the authors themselves. 
It is impossible for us to travel through these minutiae 
of classification, the discussion of which, moreover, 
would be neither interesting nor instructive to the 
reader; the system here followed is nearly identical 
with that of Mr. G. R. Gray, which in its turn is 
founded upon that of Cuvier. The latter great natu- 
ralist divided his order of passerine birds into five great 
families, to which he gave the names of Dentirostres, 
Fissirostres, Conirostres, Tenuirostres, and Syndactyli; 
the first four being characterized by peculiarities in the 
conformation of the bill, and the last by the structure 
of the feet, the outer toe in each foot being united to 
the middle one throughout nearly the whole of its length. 
Of the birds thus distinguished, the majority are now 
generally admitted to be nearly allied to those forming 
Cuvier’s group of the Fissirostres, with which they may 
well be associated in a single tribe or suborder ; the 
remainder (the Hornbills) approach the Crows in their 
general structure, and may be placed with them in the 
tribe of Conirostres. This leaves four divisions which 
may be briefly characterized as follows : — 
1. Fissikostees, with the bill usually more or less 
depressed at the base, and the gape wide, opening as 
far back as the eyes — see Plates 5 to 7. 
2. Tenuirostres, with the bill much elongated and 
slender, and the gape not so wide as in the preceding 
group— see Plates 8 and 9. 
3. Dentirostres, with the upper mandible more 
or less curved, hooked at the tip, and armed with a 
single tooth on each side — see Plates 10 and 11. 
4. Conirostres, with a stout and usually straight 
conical bill, in which the upper mandible is either 
smooth at the edges or toothed throughout— see Plates 
12 and 13. 
It is to be observed, however, that the characters 
above given are only to be regarded as appertaining to 
the groups generally ; as from the gradual passage of 
the one into the other, it sometimes becomes necessary, 
in order to avoid violating evident affinities, to place a 
given bird rather arbitrarily in the group to which it 
belongs by its general characters, although it may 
not distinctly present those expressed in the name of 
the group. 
Von. T. 35 
