Page 449. 
370 ON THE ANATOMY OF PASSERINE BIRDS. 
soft parts are concerned, at least) by a correlation of the non-varying 
details. No Passerine bird being otherwise, they probably had (1) 
the hallux alone of all the toes directed backwards, (2) short, simple 
colic ceca, (3) a nude oil-gland, together with the special pterylosis of 
the group, (4) only one carotid artery, the left, (5) a sternum with a 
single notch on each side of the carina, together with a bifurcate 
manubrium, (6) a truncated vomer with the anterior angles of which 
the nasal cartilages joined, (7) a peculiar insertion to the tensor 
patagii brevis muscle of the wing. ’ 
As in all but the Eurylemide, the deep flexor tendon of the hallux 
is free from that to the other digits of the foot, at the same time that 
the Eurylemide agree with by far the majority of the class Aves in 
this respect (whilst in the characterizing features above stated they 
are completely Passerine), it is evident that the ancestral type which 
forms the basis of our definition, lived at a period prior to the loss 
of the vinculum between the pedal deep flexor tendons, because the 
probability that the vinculum may have reappeared in them in a con- 
dition identical with that in other birds is infinitely small. This view 
is confirmed by the nature of the syrinx, as far as we are acquainted 
with it, J. Miiller not having been able to detect any intrinsic muscles 
in Corydon sumatranus,* the only species he had the opportunity of 
examining. And the length of the first primary among the remiges 
tells the same tale. 
The order Passeres falls, therefore, into two sections to start with : 
—those with the hallux not free, the Eurylemidex; and those with the 
hallux independently movable. This latter suborder may be again 
divided up in the manner suggested in Part I. of this communication.t 
I much regret that, not having been able, as yet, to obtain any of the 
Eurylemide in spirit, I have not had an opportunity of making out 
the arrangement of the tensor patagii brevis muscle at its insertion. 
From skins however, I have been able to procure the skulls, with the 
palates uninjured, of Hurylemus ochromelas, Cymbirhynchus macro- 
rhynchus, and Calyptomena viridis. The first and last of these are 
figured here (figs. 1 and 2), Cymbirhynchus agreeing very closely with 
Eurylemus. The truly Passerine nature of the vomer at its anterior 
end, with the alinasal cartilages ossified in connexion with them, is 
undoubted; at the same time the more than usually transverse and 
lengthy maxillo-palatines with their unexpanded knobbed ends are 
worthy of notice. Oalyptomena is seen to resemble the other genera 
in this latter point, though the vomer is much narrower throughout. 
The feeble development of the postero-external or “ transpalatine” 
* Loc. cit. p. 32. 
+ ‘Proceedings of the Zoological Society,” 1876, p. 518. (Supra, p. 366.) 
