380 PALEONTOLOGY 



dius, n, and ulna, u) ; they are both strong, are both distinct, 

 are firmly articulated to the arm-bone (Ji) by a joint, which, 

 although well knit, allows great extent and freedom of motion 

 in bending and extension ; and, besides this, the two bones 

 are reciprocally joined so as to rotate on each other, or rather 

 the radius upon the ulna, carrying with it, by the greater 

 expansion of its lower end, the whole paw, which can thus be 

 turned " prone" or " supine ;" whereby its application as an 

 instrument for seizing and tearing is greatly advantaged. The 

 humerus or arm-bone (Ji) is remarkable for the extension of 

 strong ridges from the outer and inner sides, just above the 

 elbow-joint. These ridges indicate the size and force of the 

 supinator, pronator, flexor, and extensor muscles of the paw. 

 To defend the main artery of the fore leg from compression 

 during the action of these muscles, a bridge of bone («) spans 

 across it as it passes near their origin. The upper end of the 

 arm-bone is equally well marked by powerful ridges for mus- 

 cular implantation, especially for the deltoid ; but these ridges 

 do not project beyond the round " head" of the bone, so as to 

 impede its movements in the socket. 



The blade-bone (scapula s) is of great breadth, with well- 

 developed processes (spine, acromion, and coracoid) for mus- 

 cular attachments ; the size and shape of this bone relate 

 closely to the volume of the muscles which operate upon the 

 arm-bone and fore limb. A small clavicular bone (b) is inter- 

 posed between a muscle of the head and one of the arm, 

 giving additional force and determination of action recipro- 

 cally to both muscles. 



Such are some of the modifications of the teeth and frame- 

 work of a beast of prey, which concur, and were deemed by 

 Cuvier to be correlated, in the organization of such animals. 



Let us compare them with those of the corresponding 

 parts in an ox (fig. 12!)). The teeth answering to the great 

 laniaries in the lion arc absent ; at most, one recognizes the 



