36 



THE BONES AND JOINTS. 



Fis 



23- 



III. THE STEENUM (Fig. 24 es, hs). 



Cuvier, I.e., p. 401, PI. XXIV, Fig. 31 ef. — Dugès, n. 27, 28. — Parker 

 and Bettany, I.e., sternum. 



The bones of the sternum are in very close relationship with the 

 shoulder-girdle, and some difference of opinion exists as to the rela- 

 tions of the several parts. 



The following parts must be regarded as midoubtedly 

 belonging to the sternum : — 



1. An anterior part, consisting of a bony and a carti- 

 laginous portion. 



a. The omosternum (Figs. 23, 34 e.s.) is a bony 

 rod, wider behind, narrower in front, and supports 



Ù. The episternum (Fig. 24 e/), a semicircular 

 plate of calcified cartilage, with a thin free border 

 of unchanged hyaline cartilage. 



2. A posterior part, which also consists of a bony 

 and a cartilaginous portion. 



Fig. 24. 



Shoulder-girdle and sternum of Rana esciilenta, tw ice nat. size. 

 The scapula and suprascapula are turned outwards. 



Connecting cartilage. h s. Sternum proper- 



Clavicles and precoracnids. W Xiphisternum^l^ 



Coracoid. o Bone. ^ 



Omostei-num. o' Calcified cartilage. . 



Episternum. sc. Scapula. 



Hyaline cartilage. sc' Snprascapula. 



