18/6.] OF PASSERINE BIRDS. 50/ 



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 flexor per/brans digitorum 

 pedis, a bond of union of one kind or other * joining them in other 

 birds. 



Keyserling and Blasiusf, in 1839, established the law that (with 

 the exception of the Alaudidaj) 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. Tbey may therefore 

 be called bilaminate, to facilitate description, the term referring to 

 the tarsal scutellation only. 



Johannes MiillerJ, 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 bronchial 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. 



Midler 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 " TracheophoiiEe," 

 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. Tn one respect he made a retrograde step, because he did 

 not lay sufficient stress upon the value of Nitzsch's work ; and this 

 was that he united the mesomyodian Passerine birds which are not 

 tracheophone with those families which constituted the more 

 expanded " Passeres" of Cuvier and with the Scansores, wavering 

 between the two classifications, which may be expressed, with the 

 employment of the term introduced above, as follows : — 



1. Passeres Acromyodi (Oscines). 1. Passeres Acromyodi (Oseines). 



2. Passeres Mesomyodi Tracheophoni. 2. Picari.e. 



3. Picari.e. a. Passeres mesomyodi 



a. Passeres Mesomyodi non- tracheophoni. 



tracheophoni. b. Passeres mesomyodi non- 



Ac. tracheophoni. 



&c. 



From the above remarks it is evident that Midler was led to lay 

 too great stress upon the nature of the syrinx as a distinctive feature 

 of the Passeres ; and although Nitzsch was unacquainted with the 



* Vide Methodi naturalis Avium disponendarum Tentamen 1872 p xl 

 t Wiegmann's 'Archiv,' 1839. i. p. 332. 

 \ Abhaud. d. Berl. Akad. 1846, p. 367. 



