96 



HITCHCOCK'S ANATOMY 



Bone is also found which is similar in position to the zygo- 

 matic process of the temporal bone in man. 



203. Bill, — Teeth are entirely wanting in Birds, their 

 place being supplied by a single horny projection on each jaw 

 known as the Bill. Teeth are not needed by these animals, 

 since mastication, where it is necessary that it should be per- 

 formed, is done by the gizzard. 



204. Ribs. — The Ribs are very firmly articulated with the 

 sternum by bone and not cartilage, so that they have a ten- 

 dency to keep the thorax as fully distended as possible all 

 the time, which is its natural position. 



Fig. 109. 205. Sternum, in what 



o Birds largest. — The Ster- 



| num is the most striking of 



f^llSS^Z^^ all the bones in a bird. It 



<wK%^^^ — c is the largest bone in their 



bodies, a flattened and some- 

 times quadrangular bone, hav- 

 ing upon its anterior surface 

 a prominent ridge like the 

 keel of a ship, for the attach- 

 ment of the pectoral muscles 

 used in flight. The size of 

 this ridge generally stands in 

 direct relation to the powers 

 of rapid flight, and hence in 

 the Humming Bird, one of the swiftest on the wing, it is 

 proportionally the largest. 



206. Clavicles, Coracoid Bone. — The Clavicles of birds 

 present a marked peculiarity. They both unite at their an- 

 terior extremity, forming a forked bone known as the Fur- 



203. What serves the purpose of teeth for Birds ? 204. How does the articulation of 

 the ribs affect the condition of the chest ? 205. Which is the largest bone in birds ? 

 How may we know the powers of flight in a bird by the keel of the Sternum ? 206. What 

 do the clavicles of birds form as they are united together? 



Bones of Sternum and Shoulder of 

 Birds, s. The Sternum, e. Notch of the 

 Sternum, co. Origin of the Sternal Bibs. 

 b. Crest. / Fourchette. c. Coracoid Cla- 

 vicle, o. Scapula. 



