BIRDS WITH TEETH. 



383 



column. With this column the broad ribs unite in the back, 

 while in front they are held together by the sternum ; and to 

 make this cradle of bones more compact and fit to resist the 

 action of the wings, and to protect the interior organs, the ribs 

 touch each other with what the anatomists call "uncinate pro- 

 cesses." Whoever is called upon to carve at the table a chicken 

 or a turkey will experience how solid and protective the construc- 

 tion of the skeleton of the body is. 



If the main body is in this way compact and immovable, some 

 other part must be so much the more flexible, and this is the 

 neck. If we watch a swan oiling its feathers with its bill, see the 

 cervical evolutions of a flamingo, or an owl sitting with its head 

 reversed, we are apt to experience a painful sensation in our necks 

 and may wonder whether the bird will assume its normal position 

 without breaking something. But all these motions are executed 

 with the most perfect ease and security, and the construction of 

 the vertebrae, which enables the birds to perform them, is simple 

 and effective. These vertebrse do not articulate with each other 

 by plain faces as the vertebrae in our bodies, but the articulations 

 are saddle-shaped, so that the prominence of one vertebra fits into 

 the excavation of the next one, and vice versa. If we take two 

 adjoining vertebrae of the neck of a bird and try their motion, we 

 shall find that this articulation admits two ways of turning from 

 one side to the other as well as up and 

 down. This saddle shape of the articular 

 face of the cervical vertebrae is found with- 

 out exception in all existing birds and in 

 no other animal. 



There are other features which are met 

 with in all birds and exclusively in them 

 for instance, the plumage. The horny bill 

 is without teeth. The vertebrae of the tail 

 are grown together and form a plowshare- 

 shaped bone. This bone supports the tail 

 feathers, which can be opened and closed 

 like a fan, and which serve as a rudder and 

 a parachute. The bones of the anterior ex- 

 tremities are transformed in such a way 

 that they form an excellent framework for 

 the wings; but, although the anatomists 



distinguish easily radius, ulna, digits, etc., one would hardly sus- 

 pect that these wing bones are perfectly analogous to those in the 

 fore-feet of quadrupeds, or in our arms and hands. 



Now let us turn our attention to the reptiles which exist at 

 the present time to the lizards, crocodiles, snakes, and turtles. 

 These cold-blooded, scaly animals seem to have nothing at all in 



Fig. 1. Vertebra op a Bird 

 with Saddle -shaped Ar- 

 ticular Face. 



