6 04 i The Sparrow-like Birds 



Garrod as " superfamilies" and to retain the term "family'" for "such groups 

 of genera as can be trenchantly separated from all others," that is, for the 

 groups ordinarily recognized as families. 



It is not deemed necessary in the present connection to go into a history of 

 the attempts that have been made to satisfactorily classify the Passeriformes, 

 especially in view of the fact that the anatomy and structure of a great num- 

 ber of forms, sometimes embracing whole "families," are practically unknown, 

 and until this knowledge is somewhere near complete all classifications of the 

 group must be regarded as more or less provisional and tentative. 



Passerine birds are in general of small or medium size, with variously shaped 

 wings in which there are nine or ten primaries, the outermost being frequently 

 rudimentary and nearly or quite concealed, nine secondaries, and usually 

 twelve (rarely ten or fourteen) tail-feathers. Of the numerous structural char- 

 acters it may be mentioned that the feet are four-toed, 1 the first toe (hallux) 

 being on the same level as the others and directed backward, while the second, 

 third, and fourth toes are directed forward; the muscles presiding over the small 

 toes are also peculiar, but need not be here described. The skull is aegithogna- 

 thous, the basipterygoid processes absent, only the left carotid artery present, 

 and the metasternum is usually two rarely four notched, while the oil- 

 gland is naked and the caeca present, though usually small. The muscles of 

 the syrinx or the voice organs exhibit a peculiar structure and, as will be 

 shown subsequently, serve as a means of defining several of the great groups. 



Following the classification of Garrod and Forbes, which seems to possess 

 advantages over others proposed, the order Passeriformes is first divided into 

 two suborders: the Desmodactyli, in which the first or hind toe (hallux) is 

 weak, the front toes more or less united, and the deep plantar tendons of the 

 foot desmopelmous, that is, having the three-branched tendon which supplies 

 the front toes united by a band or vinculum at its point of crossing with the 

 tendon which supplies the hind toe. This includes only the superfamily Eury- 

 l(zmid(Z, or Broad-bills. 



In the second suborder the Eleutherodactyli the hind toe (hallux) is 

 the strongest toe, the feet eleutherodactyle or with the front toes usually free, 

 and the deep tendons of the foot schizopelmous, or without the band or vinculum 

 at the crossing point of the tendons supplying the front and hind toes. This 

 suborder embraces practically all passerine birds and is divided into three super- 

 families : the Clamatores, in which the muscles of the syrinx are anisomyodous, 

 that is, with these muscles "unequally inserted, either in the middle or upon 

 only one or the other (dorsal or ventral) ends of the bronchial semirings," and 

 the Pseudoscines and Oscines, in which the syringeal muscles are diacromyo- 

 dous, or with the muscles "attached to the dorsal and some to the ventral 

 ends of the bronchial semirings, these ends being, so to say, equally treated." 

 In the Pseudoscines there are only two or three pairs of these syringeal muscles, 

 while in the Oscines there are four or five pairs. 



1 Except in Cholornis, in which the fourth is abortive. 



