544 MR. W. A. FORBES ON THE GENUS ORTHONYX. [June 6, 
6. Contributions to the Anatomy of Passerine Birds.—Part 
V.! On the Structure of the Genus Orthonyx. By W. 
A. Forses, B.A., Prosector to the Society. 
[Received June 5, 1882.] 
The position in the series of Passeres of the genus Orthonyx has 
for many years been a moot point with ornithologists, Johannes 
Miiller having long ago” surmised that these birds might be tracheo- 
phones, and so connected with the Neotropical Dendrocolaptide. 
Some recent writers (e.g. G. R. Gray, Bonaparte, and Salvadori) 
have placed them in, or in the neighbourhood of, the Menuride ; 
Sundevall, on the other hand’, assigns them a position amongst his 
Cichlomorphe Brevipennes. 
Up to the present time the formation of their soft parts, and par- 
ticularly of the syrinx, has remained unknown—a deficiency in our 
knowledge I am now able to supply by my dissection of both the 
Australian and New-Zealand forms. For my specimens of the 
former (Orthonyx spinicauda) I am indebted to the kindness of Mr. 
E. P. Ramsay, of the Australian Museum ; for a pair of the latter 
(O. ochrocephala) to that of my friend Prof. Jeffery Parker, of the 
University of Otago. 
Both forms are typical Singing-birds (“ Oscines Normales”’), with 
a well-developed Oscinine syrinx with its normal complement of four 
pairs of muscles. Of these the short anterior muscle runs to the an- 
terior end of the third bronchial semiring alone in O. spinicauda ; 
whilst in O. ochrocephala this ring receives its muscular supply 
from a fasciculus of the Jong anterior muscle. They thus differ 
essentially from Menura, with which they have been associated, that 
bird having but three pairs of muscles, peculiarly arranged *. 
In this, as in all other points examined—with one exception in the 
case of Orthonyx spinicauda—these birds quite resemble the normal 
Passeres, as they do in having the bilaminate tarsus and reduced 
first” (tenth) primary nearly always associated with the normal 
Acromyodian syrinx. Orthonyx spinicauda, however, has a pecu- 
liarity quite unknown to me in any other bird, inasmuch as its 
carotid artery, the left alone of these vessels (as in all Passeres) 
being developed, is not contained anywhere in the subvertebral canal, 
but runs up superficially in company with the left vagus nerve to 
near the head, where it bifurcates in the usual manner. This is 
just the same arrangement as that which occurs in many of the 
Parrots—all those in fact included in Garrod’s ‘‘ Psittacide,”’ >—save 
that in them the right carotid artery as well is present, running as 
usual in the hypapophysial canal. 
1 For Part IV. see P. Z. 8. 1881, p. 435. 
2 In 1848. Vide ‘ Vocal Organs of Passeres,’ Garrod’s edition, p. 36. 
3 «Tentamen,’ pp. 9 & 11. 
4 Garrod, Coll. Papers, pp. 362-364. 
© Goll. Papers, p. 255. 
