44 A SYNOPSIS OF ANIMAL CLASSIFICATION. 



Class V. AVES * Warm -blooded Vertebrates, show- 

 ing many reptilian characters, but 

 differing from them in the pos- 

 session of feathers, which are epi- 

 dermic structures closely related to 

 scales. The anterior limbs, modi- 

 fied to form wings, generally give 

 the animal the power of flight. 

 Quadrate bone movably articulated 

 with the skull. A single occipital 

 condyle. 



The classification of this group which has obtained until recently, 

 and the one still found in the majority of text-books, is artificial in 

 character and results from an attempt to differentiate for convenience 

 the enormous number of living species which are too nearly alike mor- 

 phologically to sanction such a division. " The Order of birds is so 

 uniform in its structural features that it is diflicult to find important 

 characters to differentiate the twelve thousand known species into con- 

 venient groups. As a result, ornithologists have raised the number of 

 minor groups into so-called Orders, which are scarcely of Family rank, 

 if we are to accept the rules in vogue in other groups of Vertebrates " 

 (Kingsley). 



For convenience the lesser groups, usually described as Orders, are 

 here retained as Sub-orders, although hardly equivalent to such groups 

 elsewhere. 



Sub-class I. SAUKUIUE Jaws containing teeth, tail elon- 

 gated, vertebrated throughout, and 

 with a pair of contour feathers to 

 each vertebra; digits of the wings 

 not anchylosed, partially free, three 

 of them provided with claws. This 

 group rests upon the remains of a 

 single fossil species (two speci- 

 mens) from the Jurassic limestone 

 of Solenhofen, Germany. 



X Archoeopteryx. 



Note. — The classification of birds as here given follows closely that of Kingsley 

 (Vertebrate Zoology, 1899) which, in its turn, is based upon the comparatively re- 

 cent investigations of FUrbringer and others. The more femiliar names for the 

 groups of carinate birds are added to Order 3. Euomithes, as its sub-divisions. 



