C. A third section consists of a single species, distinguished by the yellow, varied with
crimson, of. the whole of its under surface; b y the deep crimson of the space between its
shoulders, as well as of its upper tail-coverts; by the white of the upper p a rt of its throat and
of the sides of its head ; and especially by the absence of barbs from the feathers of the last-
named parts, and of the head generally, the shafts being so spread out, on the upper part o f the
head particularly, as to have the flattened and curled appearance of ebony shavings. I t is the
6 . Pter. ulocomus; with the bill crimson, blue, purplish red, and yellow, in longitudinal
masses.
D. A fourth section of the Ara§aris may be distinguished by the birds composing it
having the throat, breast, and belly of a single colour, different from that of the upper surface.
In the first of the species comprised in it the colours of the hinder p a rt of the tru n k are
singularly counterchanged, the upper tail-coverts being yellow, while the under are crimson;
whereas in all the other Ara^aris in which these feathers differ in colour, it is the upper that
are crimson, and the under that are yellow. The species are
7- Pter. hypoglaucus; with the under surface, except the tail-coverts and the hinder part
of the neck, blueish grey.
8 . Pter. Baittoni; with the under surface, sides of the face, and forehead yellow.
E. In the fifth section of the Ara^aris are comprehended two species, in which the whole
of the under surface, except the throat, is yellow or greenish yellow; the upper tail-coverts
are, as usual, crimson; and the head and neck are of a much darker colour than the rest of
the body. The colour of the head and neck in the birds of all the preceding sections is
similar in both sexes: in those of the present section, these parts are black in the males and
brown in the females.
9- Pter. viridis; with the upper mandible yellow above and chestnut below, and the
lower mandible black throughout, except a t its base.
10. Pter. inscriptus; with the bill yellow, black on its culmen, at its tip and base, and
blotched with black along its cutting edges.
F. The sixth section of the Ara§aris agrees with the preceding one in having the
anterior part of the birds comprised in it of a darker colour than the remainder of the plumage,
and in having those parts which are black in the males differently coloured in the females,
except the back of the head in one species. The dark colour of the under surface extends
6
over the breast as well as the throat. The ear-coverts, and a crescent-shaped band separating
the dark colour of the upper part of the neck from the green of the back, are yellow. In this
section we find, for the first time, the upper tail-coverts destitute of any peculiar colour, and
agreeing in tint with the adjoining part of the back.
11. Pter. maculirostris; with the bill white, marked on the sides of the upper mandible
with about four large black blotches.
12. P te r. Culik; with the bill red at the base, and black throughout the remaining two
thirds of its length.
G. The seventh and last section o f the Ara^aris comprehends two species, distinguished by
the simplicity of their colouring from all those which have been previously noticed. They are
of a nearly uniform colour, and are entirely destitute of those striking tints which vary so
agreeably the plumage of the remainder of the genus. In both of them the upper part of the
throat is white; in one of them the cheeks also are white, while in the other they are blue.
13. Pter. prasinus; with the under tail-coverts and tips of the tail-feathers brown.
14. Pter. sulcatus; with the under tail-coverts of the same green as the belly, and the
tips of the tail-feathers tinged with blue.
In this last section, and especially in the last-named species, the bill acquires its maximum
of deviation from the typical form of the family. Instead of being, as in the Toco Toucan, of
greatly disproportionate length; compressed on the sides so as to be comparatively thin in its
horizontal diameter while it is elevated in its vertical he ig h t; strongly arched along its upper
edge, which is so narrow as to be almost sharp; and thin and light in its tex tu re : it becomes
in the Grooved-billed Aragari in every respect, as it were, condensed; its length is diminished
so as to approach, in some degree, to the dimensions observable in certain Barbets, such
as the Bucco grandis from the Himalayan mountains; its sides, though flattened and deeply
grooved, are not approximated to each other, the horizontal or lateral diameter of the bill
almost equalling its vertical height; the culmen is broad and flattened; and the whole substance
is comparatively solid, and conformable to the structure observable in the approximating
genera. In the form of its bill no less than in the colouring of its plumage the Pter.
sulcatus is the most aberrant species of the [family; it ought probably to be regarded as the
type of a peculiar genus, and I should not have hesitated in so considering it, but for the
intervention of the Pter. prasinus, which possesses most of its characteristics, though in a less
marked degree, and which therefore connects it so immediately with the Ara§aris in general as to