A D V E R T IS E M E N T .
Mr. Swainson’s contributions to the following pages have the letters Sw. subjoined, except
in one or two instances, where they have been. accidentally omitted. It is to be understood,
however, that all the remarks on natural arrangement are his, and that the specific names
and synonymes are given on his authority, having been either supplied or revised by him.
In the descriptions, “ Werner’s Nomenclature, by Syme,” has been adopted as the
standard for the names of the colours, the specimens having been invariably compared with the
coloured patterns previous to noting down the hue of the plumage. The measurements are
in inches and lines, or twelfth parts of an inch. The total length of the bird is measured
from the tip of the bill to the end of the tail, the neck being on the stretch. In the F alco-
NID2E and STRiGiDiE, the length of the longest quill'when plucked from the wing is given ;
but this having been found inconvenient in practice, the length of the folded wing from the
tip of the longest feather to the bend of the carpal joint is recorded in the descriptions of the
succeeding families. The dimensions of the bill are generally taken both from the feathers
of the forehead, following the curve of its ridge,—and from the rictus or angle of the mouth,
in a straight line to the tip. The tail is measured from its extremity to the insertion of the
quills in the coccyx; and in the length of the tarsus are included its articular cartilages;
that is, the points of the compasses were placed in the centres of the tarsal and metatarsal
joints. The lengths of the toes are given separately from the nails.