Order PASSEllIFORMES. 



PASSERINE BIEDS. 



Bill hard and horny, never extensively membranous, softly tumid, nor 

 cered; nostrils without open communication; greater wing-coverts not 

 more than one-half the length of the secondaries; primaries usually ten, 

 more rarely nine; rectrices twelve, rarel}'' ten; feet adapted for perching; 

 hind toe and claw well developed and inserted on the level of the anterior 

 toes ; hind claw equal to, or longer than, the claw of middle toe ; anterior 

 toes three in number, never versatile, always free except when webbed 

 or fused at base. 



The order Passeriformes includes nearly as many species, among 

 Philippine birds, as all the other orders combined. Most of the species 

 of this order are less than 200, and very few of them are more than 300, 

 millimeters in length. The small birds belonging to other orders are 

 extremely few. Most ornithologists consider the Passeriformes to be 

 the order of highest rank among birds, chiefly because of the highly 

 developed vocal powers of many of the species. In the arrangement of 

 the families of this order, the Turdidce, Fringillidw, and Corvidce have 

 variously been assigned to the place indicating the highest development. 



Suborders.* 



a'. Tarsus with its hinder portion somewhat compressed, but the posterior edge 

 rounded and entire Mesomyodi, or Clamatores (p. 413) 



a^. Tarsus with its liinder portion compressed and forming a sharp edge; or else 

 tlie hinder face rounded and distinctly divided by transverse joints. 



Acromyodi, or Oscines (p. 422) 



.Suborder .ME8().MY0DI. 



Characters the same as those given in the key to Suborders. 



Family PITTID^. 



Kectrices twelve; tarsus booted, or with obsolete, diagonal divisions. 



* Apart from the cliaracters presented by the tarsal envelope, this division 

 into suborders is fully justified by internal structures, but as these can not be 

 examined in skins they are omitted above. 



Key to the suborders of Passeriformes based upon internal characters. 



a^. Intrinsic muscles of the syrinx fixed to the middle of the bronchial semirings, 

 the muscles simple, small, and few Mesomyodi 



a". Intrinsic muscles of the syrinx fixed to the ends of the broncliial semirings, 



the muscles complex and numerous Acromyodi 



83286 ■ 413 



