218 



AVES. 



size is inferior, and the ground-tint of their plumage commonly green, with some red or yellow on the 

 throat and breast ; [the female is chestnut-brown where the male is black, the tail much graduated, 

 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 

 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 he'd 

 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 

 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, 

 and furnished on each side with three peculiar muscles, [the bony ring at the divarication of the 

 Ironchi 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 

 set in motion by 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] 

 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 

 hand]. Assisted by their hooked bill, they clamber about the branches of trees; nestle in hollow 

 trunks ; and have a loud and harsh voice in a state of nature. Nearly all of them are adorned 

 with gorgeous colours, and they are scarcely found out of the torrid zone, [except in the southern 

 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 Quadntmana do the Cantivora. 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 Passerince, and the rest of the yoke-footed 

 genera without exception,— they have absolutely nothing in common with the other Zygodactyli that should entitle 

 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 



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 flattened, 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- 

 senna, 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 Passerince, but which 

 are lower in the scale than the present one, or, in other words, less distantly removed 

 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. 



