THE SKELETON 45 
In the anterior part of the thorax the vertebral extremity of 
each rib is divided into two parts, “head” or “capitulum,” and 
“tubercle”; the former is attached to the side of the body of the 
vertebra, the latter to its 
transverse process; the 
former attachment corre- 
sponds to the interspace 
between the vertebra, the 
head of the rib commonly 
articulating partly with 
the hinder edge of the 
body of the vertebra ante- 
cedent to that which bears 
its tubercle. Hence the 
body of the last cervical 
vertebra usually supports 
part of the head of the first 
rib. In the posterior part 
of the series the capitular 
and tubercular attach- 
ments commonly coalesce, Fria. 14.—Sternum and strongly ossified sternal ribs 
and the rib is attached of Great Armadillo (Priodon gigas). ps, Presternum ; 
xs, Xiphisternum. 
solely to its corresponding 
vertebra. The number of pairs of ribs is of course the same as that 
of the thoracic vertebree. 
The circumstance that in some of the Anomodont reptiles and 
Fic. 15.—Skeleton of Lion (Felis leo). cd, Caudal vertebre ; cp, carpus; cr, coracoid process 
of scapula ; cv, cervical vertebre ; d, dorsal vertebrae ; fb, fibula; fm, femur; h, humerus; il, 
ilium ; isch, ischium; 2, lumbar vertebre ; m, metatarsus ; mc, metacarpus ; 7p, patella ; pb, pubis ; 
ph, phalanges ; pv, pelvis; r, radius; s, sacral vertebre; sc, scapula; sk, skull; th, tibia; ts, 
tarsus ; u, ulna; zy, zygomatic arch. 
Labyrinthodonts the capitula of the ribs articulate with the inter- 
central elements of the vertebral column has suggested, as in the 
