404 



COLLEGE ZOOLOGY 



The vertebral column serves as a supporting axis for the body. 

 Its structure, however, is such as to allow movement, since it 

 is composed of a number of movable parts, the vertebra. The 

 vertebrae develop from cartilaginous tissue which forms a 

 sheath around the notochord. A typical vertebra consists of 



SCP 



FE 



PU 



31 JH 



FIG. 348. Diagrams of A, fore limb and girdle, and B, hind limb and girdle 

 of a vertebrate. I-V, digits; actb, acetabulum; CL, clavicle ; cn.i, en. 2, cen- 

 tralia; COR, coracoid ; dst. 1-5, distalia; F E, femur; FI, fibula; fi, fibulare; 

 gl, glenoid cavity; HU, humerus; I L, ilium; int, intermedium; IS, ischium; 

 mtcp.i5, metacarpals ; mtts.i5, metatarsals; .p. cor, procoracoid ; ph, pha- 

 langes ; P U, pubis ; RA, radius; ra, radiale ; SCP, scapula; TI, tibia; 

 ti, tibiale; U L, ulna; ul, ulnare. (From Parker and Haswell.) 



a supporting basal portion, the centrum (Fig. 346, cri), a dorsal 

 or neural arch (no), which protects the spinal cord (sp.c), a 

 neural spine, which extends dorsally from the center of the 

 neural arch and serves for the attachment of muscles, and a 

 transverse process (t.p) on each side of the centrum to which a rib 

 (r) may be joined. 



