1 8 THE SKELETON OF THE CAT. 



cates herewith the capsule of the atlanto-occipital articulation. 

 In the dorsal part of the capsule a short 

 strong ligamentous strand is developed, 

 connecting the caudal border of the dorsal 

 arch of the atlas with the tip of the 

 cranial projection of the spinous process 

 of the axis. 



The dens or odontoid process is 

 held in place by the transverse liga- 

 ment (Fig. 14, b} of the atlas, which 

 passes across the process as it lies with- 

 in the vertebral canal of the atlas. The 

 transverse ligament is attached at its 



OR DENS. two ends to the medial surface of the 



First three cervical ver- sideg of the atlas at about the {on 



tebrse and base of the skull, 



with dorsal surface re- where the dorsal and ventral arches of 



moved. a, ligamentum ,, ,, 1]n : tf > 



longitudinaleposterius; 6, l 



transverse ligament of the From the cranial end of the odontoid 



atlas; c. ligamenta alaria; .. . . .. 



tt, odontoid process; e, oc- process the two ligamenta alana (Fig. 

 cipital condyles; i, 2, 3, l ^ f\ diverge craniolaterad to the rough 



the first three cervical ver- 



tebrse; 4, basal portion of ventromedial angle of the condyles of 



the occipital bone. the occ i pita l bone. 



II. RIBS. COST.E. (Figs, i and 15.) 



The cat has thirteen pairs of ribs. One of the fifth pair 

 (Fig. 15) may be taken as typical. It is a curved flattened rod 

 of bone attached at its dorsal end to the vertebral column, 

 and at its ventral end to a cartilage (costal cartilage, Fig. 

 15, /") which serves to unite it to the sternum. 



The most convex portion of the bone is known as the 

 angle (e). Each rib presents a convex lateral and a con- 

 cave medial surface, a cranial and a caudal border. The 

 borders are broad dorsad and narrow ventrad, while the sur- 

 faces are narrow dorsad and broad ventrad. The rib has thus 

 the appearance of having been twisted. 



The rib ends dorsad in a globular head or capitulum (a), 

 by which it articulates with the costal demifacets of two con- 

 tiguous thoracic vertebrae. Between the capitulum and angle 



