218 
AVES. 
size is inferior, and the ground-tint of their plumage commonly green, with some red or yellow on the i 
and the furcula (fig. 103) complete. ' 
Among the Aricaris are certain species more vividly green than the rest, the beak of which has a deep, lateral, ; d 
longitudinal furrow ; they are the Groove-bills {Aulacorynchus, Gould). The Aricaris generally are more varie- | 
gated than the true Toucans, to which they bear nearly the”same relationship which the Jays and Magpies hold { I 
the nostrils are pierced ; together with a thick, fleshy, and rounded tongue : two circumstances which 
impart the greatest facility in imitating the human voice. Their inferior larynx, which is complicated. 
set in motion hy a greater number of muscles than are found in other birds, [whence especially results 
the remarkable mobility of the upper mandible]. They have very long [and remarkably slender] 
hemisphere], but are found in both continents, the species of course differing in each. Every 
large island even has its own species, the short wings of [many of] these birds incapacitating 
them from traversing great tracts of sea. The species are therefore extremely numerous, and are sub- 
divided according to the form of the tail and some other characters. 
[This extensive group is obviously an ordinal division of the class, and should doubtless rank first in the series 
of Birds, preceding the Birds of Prey, as among Mammalia the Quadrumana do the Carnivora. If we except the 
trivial character of their outer toe being reversed, — and their foot even is in all other respects extremely different, 
and covered with small tubercle-like scales, instead of plates as in all the Passerin<e, and the rest of the yoke-footed 
them to range in the same special division : their whole structure is widely at variance ; and if there be one group 
more than another to which they manifest any particular affinity, it is that of the diurnal, Birds of Prey, which we 
conceive should range next to them, though still very distantly allied. They certainly accord with the Falcons 
more than with any other bird in the contour of the beak, and the nostrils are analogously pierced in a mem- 
brane termed the cere : they have a similar enlargement of the oesophagus, which occurs in no other zygodactyle 
are lower in the scale than the present one, or, in other words, less distantly removed 
Fig 104— Sternum of Parrot apart than all are from the latter; that they have not been generally recognized as 
thus insulated, which all have acknowledged to be the case in the instance of the 
Parrots, is attributable to their equally constant distinctive characters being less obvious externally. 
throat and breast ; [the female is chestnut-brown where the male is black, the tail much graduated, I 4 
with the Crows. They appear to be less carnivorous]. 
The Parrots {Psittacus, Lin.) — 
Have a stout, hard, solid beak, rounded on all sides, and enveloped at base by a membrane in which 
and furnished on each side with three peculiar muscles, [the bony ring at the divarication of the 
bronchi being besides incomplete, so as to permit of dilatation and contraction,] further contributes to 
the same object, [if, indeed, it be not entirely produced by the latter means]. Their vigorous jaws are 
intestines, without coeca ; and subsist on fruit of all kinds [together with bulbs and other succulent 
parts of vegetables in many instances, holding their food up to the mouth with one foot, as with a Ji 
hand]. Assisted by their hooked bill, they clamber about the branches of trees; nestle in hollow jl 
trunks; and have a loud and harsh voice in a state of nature. Nearly all of them are adorned |j 
with gorgeous colours, and they are scarcely found out of the torrid zone, [except in the southern ||i 
genera without exception, — they have absolutely nothing in common with the other Zygodactyli that should entitle 
bird, but which is glandular as in the Pigeons, secreting a lacteal substance with 
which the young are at first nourished, (the Parrots and Pigeons being almost the 
only birds which subsist exclusively on vegetable diet at all ages). The stomach is 
but slightly muscular, and we have found it enormously enlarged in old cage spe- 
cimens ; intestines singularly long and slender, as before stated ; and there is no 
gall-bladder, a particular in which the Parrots accord with the Toucans, the 
great Cuckoo group, and that of the Pigeons. The sternal apparatus (figs. 104 and 105) 
differs least from that of the diurnal Birds of Prey, the medial ridge being however 
rounded anteriorly, and the furcula slight and peculiarly fiattened, being least unlike 
that of the Pigeons, while in one subdivision of Parroquets it is absent altogether. 
From the rest of the zygodactyle birds, the Parrots differ remarkably in their intel- 
ligence and docility, qualities in which some species are unsurpassed by any member 
of the class ; while the other tree birds not framed on the definite type of the Pas- 
serinve, are with few exceptions remarkably devoid of intelligence, and incapable of 
receiving instruction. 
It may further be noticed, that all the numerous tribe of Parrots conform in every 
essential detail of their organization, being framed on an especial subtype, which, 
however it may admit (like every other) of subordinate modifications, exhibits no 
indication of a passage or transition into any other form : the same remark applies 
to several of the preceding groups that do not pertain to the Passerints, but which 
