THE 



on this boiK- towards the middle line (Figs. 32, 34), where it 

 widens out. and is united by its external margin with the sternum, 

 thus forming the precoracoid as already described, see p. 40. 

 These connections are best seen in young animals, as is shown in 



Fi y- 34- 



The clavicle (<.-J) is of ossifying cartilage; the cartilage (c). the 

 epieoraeoid, is very large, and hyaline, and at d runs directly into 

 the epicoracoids. which are here united mesially by ligament. In 

 the fully developed animal the whole of the epieoraeoid changes to 

 calcined cartilage, as also does the precoraeoid lying in the groove 

 of the clavicle. 



B. BOXES ui THE FORE LIMB. * 



1. The arm has but one bone. 



The humerus. os linmeri (Figs. 35, 36, 37). The shaft of the 

 humems is. on the whole, cylindrical, the middle part being the 

 Fig. 35- Fig. 36. 8 37. 



Humerus of Rnnn et- 

 cultnta, female, seen 

 from below. 



Humerus of Kana tt- 

 cuknta, male, seen 

 from below. 

 Figures twice natural size. 



r Anterior extremity. tf Posterior extremity. 



cm Crista medialis. t 



Humerus. of Rana 

 tn, female, 

 outer skle. 



,-rf Crista deltoidea. 



narrowest ; its dorsal surface is slightly concave, the ventral surface 

 convex. In the upper half the cylindrical form is indistinct, from 

 the presence of a well-marked crest (crista deltovha) upon the under 

 'r ventral surface. The hinder half of the bone lias verv different 



