THE ANIMAL BODY 



ns 



whole arise PROCESSES for movable articulation with its 

 neighbors, the attachment of muscles, etc. Between the 

 vertebrae of the Mammals are 

 cushions of cartilage which ab- 

 sorb shock. (Fig. 79.)' 



In some forms, RIBS are at- 

 tached to the transverse pro- 

 cesses of certain vertebrae. 

 These extend outward and down- 

 ward within the body wall, and 

 become attached in the mid- 

 ventral line to the breast bone 

 (STERNUM). Thus, in the adult 

 of the higher Vertebrates, the 

 series of centra of the vertebrae 

 come to occupy the position 

 formerly held by the notochord ; 

 while above, the neural arches 

 encircle the NEURAL CANAL con- 

 taining the spinal cord; and below, the transverse pro- 

 cesses, ribs, and sternum surround the anterior portion of 

 the coelom. (Fig. 75.) 



The Vertebrate head, containing the anterior end of the 

 alimentary and neural canals, the brain, and the chief sense 

 organs, is protected in the lower Fishes by a case of cartilage. 

 In higher forms the cartilage is replaced by a bony SKULL 

 which articulates with the first vertebra of the backbone. 

 JAWS, or supporting structures of the mouth, are attached 

 to the skull. 



The skull, vertebral column, ribs, and sternum together 

 comprise the AXIAL skeleton, from which is suspended the 

 APPENDICULAR skeleton, or bony frame-work of the paired 

 appendages. This is relatively simple in the anterior (pec- 



FIG. 79. A typical human ver- 

 tebra (tenth thoracic) viewed from 

 the dorsal surface. C, centrum; lam, 

 ped, neural arch; ns, neural spine; 

 prez, anterior articulating process; 

 tr, transverse process; i>f, neural 

 canal through which the spinal cord 

 passes. (From Walter, after Spalte- 

 holz.) 



