78 DESCRIPTIONS OF THE GROUPS OF BIRDS 



Under this appellation I have brought together the two 

 very distinct families of Rhamphastida (comprising the tou- 

 cans and aricaris), and Musophagidee (consisting of the plan- 

 tain-eaters, touracos, and colies); the former restricted in 

 its distribution to South America; the latter peculiar to the 

 eastern hemisphere, and with the exception of two or three 

 species of coly, to Africa. The name, if not quite all that 

 may be wished, is nevertheless the least objectionable that 

 has yet occurred to me : it is appropriate enough to all 

 except the colies. There is considerable similarity in the 

 conformation of the skeleton in these two families, the princi- 

 pal difference consisting in the very small size of the sternum 

 throughout the Musophagidee, and in the imperfection of the 

 clavicles, or lateral halves of the furcula, in the true toucans, 

 though not in the closely allied genus of aricaris {Pteroglos- 

 sus), to judge from FHerminier's representation of the sternal 

 apparatus of Pt. aricari, wherein the furcula is made to re- 

 semble that of a touraco : in both, there are no false ribs at- 

 tached to the anterior anchylosed vertebra of the pelvis, * a 

 very peculiar character. The beak is inflated and permeated 

 by osseous fibres in the plantain-eaters (Musophaga), and to 

 a less extent in the touracos [Corythaix) and nape-crests 

 {Chizmris); with proportionally thin parietes, as in the tou- 

 cans (Rhamphastos), where the inflation and consequent at- 

 tenuation of its substance attain their ultimatum. The 

 tongue, which in the toucan family is barbed throughout its 

 length with lateral appendages like a feather, is in the toura- 

 cos similarly fringed, but towards the tip only, to a variable 

 extent. The digestive organs chiefly differ in the presence 

 of a small gall-bladder in tfie Musophagidee, which is wanting 

 in the Rhamphastidae. Lastly, of their external characters, 

 it may be remarked that both have only ten tail-feathers, that 

 their wings are much rounded, and more or less of their body 

 plumage loosely webbed. They subsist principally (and some 

 of them it would appear wholly) on fruits ; and, excepting 

 the colies, are remarkable for the airy lightness of their move- 

 ments. 



The distinctions between the Rhamphastida and Muso- 

 phagidee, however, are considerably more obvious than their 

 points of similitude, being principally external. The modi- 

 fication of the foot is very different, and in the former group, 

 to which I shall now restrict myself, typically zygodactyle. 

 From the singularity of their appearance, occasioned by the 



1 At least, I can perceive no traces of such having been broken off, in the 

 skeletons to which I have access. 



