320 SYSTEMATIC SYNOPSIS. — PASSERES — OSCINES. 
is scarcely or not half as long as the Ist; secondaries and their coverts also very short; all 
these quill-feathers broad and stout. An acute, thin-bladed and somewhat faleate wing, of 
surpassing volatorial power, results from PMI dications Tail of 12 rectrices, perhaps 
abnormally only 10, usually forked, or at least emarginate, and often deeply forticate, the 
outermost feathers beg in this latter case narrowly linear in shape for a considerable dis- 
tance. Feet short, small, 
and weak, ill-adapted to 
secure foot-hold, and very 
badly formed for walk- 
ing. Swallows scarcely 
use their feet for locomo- 
tion, relying mainly upon 
their prowess of pinion. 
The tarsal envelope thor- 
oughly Oscine in struct- 
ure, being scutellate in 
front and laminate behind; 
it is sometimes partially, | 
or almost entirely, feath- 
ered; the tarsi are com- | 
monly shorter than the | 
lateral toes. The digits 
possess the normal number 
of phalanges; the basal | 
phalanx of the middle | 
digit is commonly coherent | 
with one or both lateral 
toes; the hallux is ordi- 
nary, and not reversible. | 
The digits are commonly 
naked and scutellate, rare- 
ly feathered to the claws. 
The claws are compara- 
tively strong, compressed, 
well-curved, and acute, 
apt for clinging. The 
plumage is soft, smooth, 
and blended, most fre- 
quently glossy or even 
AN | iridescent, but sometimes 
Hc ia a ip 7h lustreless. | Head _ short, 
aK mM NW Wii WU: hi Ni Ng broad, and depressed ; 
Zi ASAD Aa NA neck short. Mouth capa-— 
Fic. 180. — Upper, European House Martin, Chelidon urbica; lower, Bank eious, its greatest width 
Swallow, Cotile riparia. (From Dixon.) 
se wan Ways (Rea Nh 
Lae 
UNG Sd ( 
equalling that of the head. 
This is a perfectly natural group, well distinguished by the foregoing characters. The 
swallows alone represent, among Oscines, the fissirostral type of structure ; they have a close 
superficial resemblance to the swifts and goat-suckers of another order, but the relation is one 
of analogy, not of affinity, though all these birds were formerly classed together in the highly 
unnatural ‘ order” Fissirostres. (See beyond, under Cypselide and Caprimulgide.) 
