Page 447. 
368 ON THE ANATOMY OF PASSERINE BIRDS. 
Fig. 7. Back view of skull of Pitta cyanura. 
8. Sternum of same. 
N.B. Although the artist has done all in his power to make clear the peculiari- 
ties of the insertion of the tensor patagii brevis in the families of birds here depicted, 
it is important to mention that in actual specimens the differences are much more 
easily recognizable than might be inferred from the figures. 
58. NOTES ON THE ANATOMY OF PASSERINE BIRDS. 
PART II.* 
In my former communication on the anatomy of the Passeresf I 
adopted a definition of the group in which was included the important, 
character made known by C. J. Sundevall in 1831, and expressed in 
the 1872 edition of his valuable ‘‘ Methodi naturalis Avium disponen- 
darum Tentamen” in the following words:—‘“‘ Hallux .... . 
per se mobilis. Musculus enim flexor hallucis longus articulum ejus 
ultimum flectens, a flexore digitorum communi perfecte solutus. (In 
avibus reliquis, omnibus, tendo hujus musculi cum tendinibus alterius 
conjungitur. Hallux igitur simul cum reliquis digitis semper flec- 
titur.)” Upupa epops, agreeing with the Passeres in this respect, is 
by the author included with them. As mentioned in my paper on the 
deep plantar tendons of birds}, I have so frequently been able to verify 
this statement of the Swedish naturalist, that I feit justified in 
making the fact part of my definition of the group. Recently, how- 
ever, from skins which have been placed at my disposal by Mr. Salvin, 
I have found reason for overthrowing the character, because in the 
Eurylemide there is a strong vinculam which joins the two muscles 
exactly in the same manner as in many of the non-passerine families. 
Eurylemus ochromelas, Cymbirhynchus macrorhynchus, and Calyp- 
tomena viridis are the species which I have examined (more than one 
specimen of each); and in all of them there is a narrow but strong 
vinculum, situated just above the metatarso-phalangeal articulations, 
and running from the tendon of the flexor hallucis longus downwards 
to the tendon of the flexor digitorum profundus. No other Passerine 
bird which I have dissected possesses this vinculum, not even Rupicola 
crocea, which has been thought by some to be intimately related to the 
* “Proceedings of the Zoological Society,” 1877, pp. 447-53. Read, May 15th, 
1877. 
+ “ Proceedings of the Zoological Society,” 1876, p. 508. (Suprda.) 
t “ Proceedings of the Zoological Society,” 1875, p. 348. (Supra, p. 298.) 
