LIMBS OF VERTEBRATES. 



395 



Fig. 377.— Diagram of a Vertebra 

 with its \ioiy (5), rib (7), breast-bone 

 (6) ; 1 , neural spine ; 2, 3, fore and 

 hind oblique processes ; 4, transverse 

 processes. 



bodies of each vertebra of a lizard, bird or mammal being 



solid bone. Figs. 375 and 376 represent the relations of the 



notochord in an adult lamprey and a young fish. 

 The vertebra of a bony fish 



or higher vertebrate consists 



of a body, with a dorsal or 



neural spine ; a pair of oblique 



processes (zygapophyses) arching 



over and enclosing the spinal 



cord ; and transverse processes^ 



bending downwards, to which 



the ribs are articulated ; certain 



of the thoracic ribs uniting 



with the stermim or breast-bone 



(Figs. 377 and 378.) 

 Vertebrae like those of fishes, 



which are hollow or concave at 



each end, are said to be amphicoelous ; those hollow in front 



and convex behind proccelous, as in most toads and frogs 



and crocodiles, and most existing 

 lizards, and those convex in front 

 Jr A and concave behind ojjisthoccelous, 



lo^'is, ^^^^Qal;;^i—y ^ as In the garpike, some Amphib- 

 ians (the salamanders and cer- 

 tain toads, Pipa and BomMnatoi-). 

 „. „ „ . Vertebrates never have more 



Fig. 378.— Thoracic vertebra of , » t , 



buzzard (Buteo vulgaris). <^, centrum than twO pairS 01 limbs, an an- 

 or body ; .s, superior spinous pro- , . n i • i • j_i i 



cess : tr, transverse process ; io, terior and hinder pair ; tne pecto- 



rib : ff, tnberculumof the rib r /3, ca- i • £ n j> ^ i x 



nituium of the rib.-After Gegen- ra] pair of fins of fishes represent 

 *"""■• the fore limbs of Amphibians and 



higher Vertebrates, and the arms of man ; the two ventral 

 fins represent the hind legs of higher Vertebrates, and the 

 legs of man. Each pair of limbs is connected by ligaments 

 and muscles to a girdle or set of bones, called respectively 

 the shoulder girdle and pelvic girdle, each girdle being con- 

 nected by muscles to the vertebral column. The shoulder 

 girdle consists of a clavicle (or collar-bone), scapula (or 

 shoulder-blade), and coracoid bone, usually a process of the 

 scapula. These bones difEer greatly in the different classes. 



