ON CERTAIN MUSCLES OF BIRDS. F217 
and Cathartide are exceptions to the above-stated rule, the first two 
having no ceca, the next two a nude oil-gland, and the last neither 
ceca nor a tufted oil-gland. 
Another myological fact comes in here to assist. A reference to 
Plate 5 (X VII.) in comparison with Table I. will show that no anomalo- 
gonatous bird has been found to possess the accessory femoro-caudal ; 
that is, B never enters into its myological formula. Such being the 
case, when a bird has a formula with B in it, at the same time that 
either the ambiens muscle is absent, or has a nude oil-gland in com- Page 119. 
bination with intestinal czca, it is certain to be a homalogonatous 
bird. That the formula of the Musophagide is A B. X Y, and the 
ambiens is present, therefore more than counterbalance the exception 
presented by the arrangement of their ceca and oil-glands. The same 
remarks apply to the Cuculide. The Cathartide possess the ambiens, 
which, in conjunction with many other Ciconiine characters, leaves no 
doubt about their position ; and the Psittaci cannot, from the presence 
of an ambiens in some of them, be placed with the Anomalogonatz, to 
which they otherwise present many points of similarity. 
Excluding the Macrochires, which have a nude oil-gland and no 
cxca, all the other anomalogonatous birds have either a nude oil-gland 
and ceca, or a tufted oil-gland and no ceca; and this definite set of 
features makes it easy to divide them up into two main orders, the 
Piciformes and the Passeriformes. 
Piciformes, Passeriformes, 
with tufted oil-gland and no ceca. with nude oil-gland and ceca. 
Pict. : Passeres. 
{ Caionit Bucconide (?). 
Ramphastide. Trogonide, 
Upupide. Meropide. 
Bucerotide. Caprimulgide. 
Alcedinide. Steatornithide. 
Coraciide. 
Momotide. 
The position of the Macrochires is uncertain. In so far as the 
mouth tends to get very broad it resembles some of the Passeriformes. 
As before remarked, none of the Anomalogonate possess the 
accessory femoro-caudal muscle. In them also the posterior margin 
of the sternum is more perfectly formed than in the Homalogonate. 
Scansorial feet are found in both divisions; but whilst those of the 
Parrots and Cuckoos exhibit a similar arrangement of the tendons of 
the toes, the Toucans, Woodpeckers, and Jacamars follow a quite 
different type. 
All the birds which present the palatal characters expressed by 
