46 A SYNOPSIS OF ANIMAL CLASSIFICATION. 



Order 2. Impennes Aquatic birds with short, paddle- 

 like wings used only for swimming ; 

 no distinction of feathered and 

 featherless areas. Feathers cover- 

 ing wings scale-like; dorsal ver- 

 tebrae opisthoccelous and movable 

 upon one another; uncinate proc- 

 esses not anchylosed to ribs; the 

 three elements of the tarso-meta- 

 tareus incompletely fused, leaving 

 slit-like foramima, a peculiarity 

 possessed by no other living forms. 

 X Aptenodytes, Spheniscus. 



Order 3. Eugrnithes Nearly all living birds belong here. 



The sternum is carinate and the 

 wings well developed. The skin 

 possesses well-marked feathered 

 and featherless areas and the wings 

 and tail are furnished with contour 

 feathers. 



X Anser, Aquila, Gallus, Passer. 



The numerous sub-divisions of this Order, considered here for con- 

 venience as Sub-orders, may be grouped in three groups in accordance 

 with a fundamental anatomical characteristic, viz. : the relationship 

 existing between the maxillo-palatine processes and the vomer as seen 

 upon the ventral side of the skull. Thus, in the desmognathous type the 

 maxillo-palatine processes are united in the median line, forming a bony 

 roof to a part of the palate ; while in the schizognathous and sgithogna- 

 thous types the maxillo-palatine processes are separated from each other, 

 leaving a median, longitudinal cleft in the bony palate. These two last 

 types are distinguished from each other by the shape of the anterior 

 end of the vomer, which is pointed in the Schizognathce and broad and 

 notched in the jEgithognatha. 



The groups and their sub-divisions are arranged as follows: 



Group A. Desmognathae. 



Sub-order i . Steganopodes x Pelicanus. 



Sub-order 2. Lamellirostres y. Anser, Cygnus, Anas. 



Sub-order 3. Herodiones yi Ardea, Ibis, Ciconia. 



Sub-order 4. Raptor es x Aquila, Strix. 



Sub-order 5. CoccygomorphcB . . x Cuculus, Halcyon. 



Sub-order 6. Psittaci. x Psittacus, Cacatua, Conurus. 



