ALLEN'S NATURALISTS LIBRARY. 



BRITISH BIRDS. 



PERCHING BIRDS-ORDER PASSERIFORMES. 



To this order belong the bulk of the known species of birds 

 in the world The characters which distinguish Passerine or 

 Perching Birds from the rest of the Class "Aves" are principally 

 anatomical, and the chief ones consist of the " aegithognathous " 

 palate and the " Passerine " arrangement of the deep plantar 

 tendons of the foot. 



The palate is said to be " aegithognathous," or " Passerine," 

 when the vomer is broadened and blunt, or truncated, at the 

 anterior end, and is not connected with the maxitto- palatines ^ 

 which, consequently, are widely separated from each other. 

 This arrangement is well shown in the skull of the Rook, one 

 of our largest Passerine birds. 



The deep plantar tendons of the Passeres are of the simplest 

 kind, the three front toes being served by the flexor perforans 

 digitorum, while the flexor longus halhicis serves the hallux or 

 hind toe only. 



There are many other characters which can be adduced for 

 the distinguishing of the Passeriformes, but the two above 

 mentioned are the most important. The order is divided 

 into four great sections, viz., A, Oscines, or Singing Passeres ; 

 B, Oligomyods3, or Non-singing Passeres ; C, Tracheo- 

 phonae, or South American Passeres ; D, Atrichornithes, 

 Australian Scrub-birds. 



Of these only Oscines are represented in the Palaearctic 

 Region, of which Great Britain forms part, and it is with the 

 I. B 



