212 VERTEBRATA. 



the nest is such as to conceal the sitting bird ; while, whenever 

 there is a striking contrast of colours, the male being gay and 

 conspicuous, the female dull and obscure, the nest is open and 

 the sitting bird exposed to view." The Duke of Argyll, on the 

 other hand, maintains that rather the nests themselves require 

 concealment, and that the structure "which most completely 

 covers up the eggs, or the sitting bird, may, and often does, 

 render the nest itself only more conspicuous." It appears to 

 be still a question whether birds build from instinct or from 

 imitation. No bird hibernates. 



Slight differences are sometimes observable between birds from 

 different localities, differences in some cases considered to be 

 specific ; but they are probably only " races " depending on local 

 causes. According to Blanford, eastern and western " races" are 

 found " passing into each other and breeding together where they 

 meet in the Levant." 



Systems of classification for birds have been numerous ; of the 

 two latest Huxley's and Garrod's the first is founded on the 

 palatal structure, the latter mainly on the disposition of the 

 muscles of the thigh. Huxley divides birds into three orders 

 Saururee, Batitse, and CarinataB, the latter comprising all known 

 living birds except the ostriches, emus, &c. The Carinatas 

 include four suborders: (1) Dromseognathse [vomer very broad, 

 united in front with the maxillo-palatine plates, receiving behind 

 the anterior ends of the pterygoid bones, &c.] : represented by 

 Tinamus only ? (2) Schizognathas [vomer various, tapers to a 

 point arteriorly, behind it embraces the basisphenoidal rostrum 

 between the palatines ; maxillo-palatines fissured] : includes 

 plovers, gulls, cranes, GallinaB, pigeons. (3) Desmognathae 

 [vomer abortive or very small ; "maxillo-palatines united across 

 the middle line, either directly or by the intermediation of ossifi- 

 cations in the nasal septum "] : includes most of the Grallae and 

 Anseres which are not Schizognathous, the Accipitres, the Scan- 

 sores, and many of the Volitores (i. e. swifts, kingfishers, hoopoes). 

 (4) ^Egithognathas [vomer very broad, truncated in front and 

 cleft behind, embracing the rostrum of the sphenoid between its 

 forks] : includes the great majority of the Passerine birds. The 

 last three " suborders " are divided into " groups." 



Of this classification it has been remarked as " questionable " 

 " how far any approach to a natural system can be based on the 

 modification of one part of an animal's structure without any 

 reference to other portions of it " (Newton). 



Garrod divides birds into two subclasses according as the 

 "ambiens" (or rectus femoris, a slender musele arising above the 



