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354 ON THE ANATOMY OF PASSERINE BIRDS. 
Corvus, together with Oerthia among the “ Pics,” “rostro superne 
compresso convexo.” 
Cuvier, in 1798*, made a great step in advance by forming an 
order “ Passeres” to include all those now so called, together with 
those non-swimming, non-wading, non-climbing, non-raptorial, non- 
gallinaceous birds in which there are not two toes of the foot retro- 
verted. : 
Nitzscht was the first to appreciate the true limits of the order, 
when in 1829 he grouped together the birds now termed PassEREs in a 
single section, entirely by themselves. 
C. J. Sundevall, in 1831, discovered that in the birds which he 
had the opportunity of examining that belonged to the order Passeres 
of Nitzsch, and only elsewhere in Upupa, the tendon of the flexor 
longus hallucis is quite independent of the flewor perforans digitorum 
pedis, a bond of ‘union of one kind or othert joining them in other 
birds. 
Keyserling and Blasius§, in 1839, established the law that (with 
the exception of the Alaudide) those Passerine birds in which the 
form of the lower larynx (named “ syrinx” by Professor Huxley) is 
what is known as ‘‘ oscine,” possess a pair of long scutes as a covering 
to the back of the tarso-metatarse. They may therefore be called 
bilaminate, to facilitate description, the term referring to the tarsal 
scutellation only. 
Johannes Miiller||, from his elaborate investigations on the struc- 
ture of the syrinx in the South-American Passeres, was led to divide 
the group into two major sections—those in which the intrinsic muscles 
of the voice-organ are inserted into the ends of the bronchial semi- 
rings, and those in which they are inserted into their middle parts. I 
would suggest the name Acromyodi for the former of these divisions, 
and Mesomyodi for the latter—an acromyodian bird being one in which 
the muscles of the syrinx are attached to the extremities of the bron- 
chial semi-rings, a mesomyodian bird being one in which the muscles 
of the syrinx join the semi-rings in their middles. It seems to me 
advisable to restrict these terms to Passerine birds. 
Miller found that among the mesomyodian Passeres there is a large 
collection of genera in which an easily recognized special type of 
syrinx exists. This group he separated off as ‘“Tracheophone,” so 
naming them on account of the large share taken by the peculiarly 
modified lower end of the trachea in the formation of the voice-organ. 
* “ Tableau Elémentaire,” p. 199, e¢ seq. 
+ “ Observationes de Avium arterid carotide communi.” 
t Vide “ Methodi naturalis Avium disponendarum Tentamen,” 1872, p. xl. 
§ “ Wiegmann’s ‘ Archiv,’ 1839, i, p. 332. 
|| ‘“ Abhandl. d. Berl. Akad.,” 1846, p. 367. 
