24 THE CLASSIFICATION OF BIRDS 



SPILENISCOMORPH^:. 



The Penguins are very highly specialised Birds, but possess 

 some peculiarities which may be archaic. In addition to the char- 

 acter that none of the feathers of the wing are differentiated into 

 quills, they possess other characters which are equally diagnostic. 

 The first digit of the manus is fused with the second in adult 

 birds ; the bones of the forearm are all flattened ; the scapula is 

 very broad, not differing very much in size from the keel of the 

 sternum. 



1. IMPENNES. 



The Penguins are entirely confined to the Southern Hemisphere 

 only reaching the Equator on the Galapagos Islands, having appa- 

 rently followed the cold Peruvian current, which flows from the 

 Antarctic Ocean along the west coast of South America. They all 

 belong to the Spliceniscidce. 



PELARGOMORPH^l. 



The Pelargomorphge comprise all the aquincubital Birds with 

 normal deep plantar tendons. They may be subdivided in various 

 ways ; but the following division appears to possess the merit of 

 demanding the fewest instances of the independent acquirement 

 of important characters, whilst each division is capable of being 

 diagnosed with ease. These subdivisions are four in number, and 

 may be diagnosed as follows : 



CHARADRIIFORMES. Pelargomorphje with schizognathous 

 palate* and schizorhinal nasals.-f- 



* The arrangement of the bones of the palate, with which Huxley's name is 

 specially associated, is admitted to be of considerable taxonomic importance, 

 though in some cases the change from one type to another has unquestionably 

 been independently made and occasionally imperfectly completed. The main 

 points are in the shape of the vomer and the coalescence of the maxillo- 

 palatines. The vomer may be broad and truncated (Passeres), narrow and more 

 or less pointed (Limicolas), or a combination of the two (Trochili). It may be 

 absent (Alcedinidce), or split into more than one (Picidce). It may also be 

 expanded behind so as to prevent the palatines from articulating with the 

 rostrum of the basisphenoid (Struthiones). The maxillo-palatines may coalesce 

 with each other across the middle line (Anseres), or be united by an ossified 

 nasal septum (Falconidre), or be free from each other (Charadriidcc). 



If wideness of distribution be an argument in favour of ancientness of origin, 



