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200 ; STRIGIDH, OWLS. 
mounted on long legs, like a crane, and has several other more important structural 
modifications. The other three families occur in this country; and the following 
accounts are sufficiently explicit to illustrate the order, without further remark 
in this connection. 
Family STRIGIDA. Owls. 
Head very large, and especially broad from side to side, but shortened length- 
wise, the ‘‘face” thus formed further defined by a more or less complete “ruff,” or 
circlet of radiating feathers of peculiar texture, on each side. Eyes very large, 
looking more or less directly forward, set ina circlet of radiating bristly feathers, 
and overarched by a superciliary shield. External ears extremely large, often pro- 
vided with an operculum or moyable flap, presenting the nearest approach, among 
birds, to the ear-conch of mammals. Bill shaped much as in other ordinary rapa- 
cious birds, but thickly beset at base with close-pressed antrorse bristly feathers. 
Nostrils large, commonly opening at the edge of the cere rather than entirely in its 
substance. Hallux of average length, not obviously elevated in any case; outer 
toe more or less perfectly versatile (but never permanently reversed), and shorter 
than the inner toe. Claws all very long, much curved and extremely sharp, that of 
the middle toe pectinate in some species. As arule, the tarsi are more or less 
completely feathered, and the whole foot is often thus covered. Among numerous 
osteological characters may be mentioned the wide separation of the inner and 
outer tablets of the brain case by intervention of light spongy diploe; the 
commonly 4-notched sternum, and a peculiar structure of the tarso-metatarsus. 
The gullet is capacious but not dilated into a special crop; the gizzard is only 
moderately muscular; the intestines are short and wide; the cceca are extremely 
long and chib-shaped. The syrinx has one pair of intrinsic muscles. The feathers 
haye no aftershaft, and the general plumage is very soft and blended. 
The Nocturnal Birds of Prey will be immediately recognized by their peculiar 
physiognomy, independently of the technical characters that mark them as a natural, 
sharply defined family. They are a highly monomorphic group, without extremes 
of aberrant form; but the ease with which they are collectively defined is a measure 
of the difficulty of their rigid subdivision, and the subfamilies are not yet satis- 
factorily determined. Too much stress appears to have been laid upon the trivial, 
although evident, circumstance of presence or absence of the peculiar ear-tufts that 
many species possess: more reliable characters may probably be drawn from the 
structure of the external ear, and facial disk, the modifications of which appear 
to bear directly upon mode of life, these parts being as a rule most highly developed 
in the more nocturnal species ; while some points of internal structure may yet be 
found correspondent. One group, of which the barn owl, Strix jlammea, is the 
type, seems very distinct in the angular contour and high development of the facial 
disk, pectination of the middle claw, and other characters; and probably the rest 
of the family fall in two other groups; but I do not deem it expedient to present 
subfamilies on this occasion. 
As is well known, owls are eminently nocturnal birds; but to this rule there are 
numerous striking exceptions. This general habit is correspondent to the modifi- 
cation of the eyes, the size and structure of which enable the birds to see by night, 
and cause them to suffer from the glare of the sunlight. Most species pass the 
daytime secreted in hollow trees, or dense foliage and other dusky retreats, resuming 
their wonted activity after nightfall. Owing to the peculiar texture of the plumage 
a 
