LIMBS OF VEBTEBBATEa. 



375 



Fig. 352.— Diagram of a Vertebra 

 with its body (6), rib (7), breast-bone 

 (6) J 1, neural spine; a, 3, fore and 

 hind oblique processes ; 4, transverse 

 processes. 



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

 solid bone. Figs. 370 and 371 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 lody, 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 rihs are articulated ; certain 

 of the thoracic ribs uniting 

 with the sternum or breast-bone 

 (Figs. 372 and 373). 



Vertebrae like those of fishes, 

 which are hollow or concave at 

 each end, are said to be amphiccelous ; 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 



«.<'''^^-r#i^j,.„r«-Trs ^^^ concave behind opisthocoelous, 

 i/>_^^%r~^wli^y^ as in the garpike, some Amphib- 

 ians (the salamanders and cer- 

 tain toads, Pipa and Bombinator). 

 ™ „,„ ,^ . , ^ , Vertebrates never have more 



Fig. 3(3.— Thoracic Tertehra of . - i- , 



buzzard (Bntco vulgaris), c, centrum than tWO pairS of limbs, atl an- 

 or body; s, superior spiiiuus pro- . ^ ^. ^ . ^ 



cess ; tr, transverse process ; io, terior and ninder pair ; the pecto- 



rib : a, tuberculum of the rib ; /?, ca- i • £ n j» y> i 



pituium of the rib.-After Gegen- ^al pair of fius 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 differ greatly in the different classes^ 



