366 THE MECHANICAL FUNCTIONS. 



length, compared with the same bones in ruminants; and the 

 latter has, besides, a large surface for its articulation with 

 the former of these bones, thus allowing of a great range of 

 motion: the radius and ulna are perfectly distinct, and play 

 extensively on each other. 



The fore feet rest on the ground by means of the second 

 of the three joints of which each toe is composed. The last 

 phalanges are raised at right angles to the former, for the 

 purpose of supporting the claws in an erect position. It has 

 been considered of such importance to preserve these formi- 

 dable instruments constantly sharp, and in a condition fitted 

 for immediate use, that an express contrivance has been re- 

 sorted to for this purpose. It consists in a sheath, within 

 which the claws, when not employed, are kept retracted, by 

 means of an elastic ligament, which constantly tends to with- 

 draw them within the sheath: and they are, at the same time, 

 so connected with the tendons of the flexor muscles of the 

 toes, that the moment these muscles are throw^n into action, 

 which is the case when the animal aims a stroke with its 

 paw, the claws are instantly drawn out, and combine in in- 

 flicting the severest lacerations.* 



Connected with the superior strength of the hind extre- 

 mities, we find the pelvis extending farther backwards, and 

 more in a perpendicular line with the femur. This latter 

 bone is longer and more slender than in the horse, but it is 

 more compact in its form, and its processes are more strong- 

 ly developed: the fibula is a separate bone from the tibia. 

 The muscles, in general, are more divided into portions, and 

 are thus capable of greater diversity of action, at the same 

 time that they have greater power than those of herbivorous 

 quadrupeds. The articular surfaces are of greater extent, arid 

 are lubricated with a more copious supply of synovia; their 

 ligaments are more delicate and more numerous; and the 



* There exists, concealed in the tuft of hair, at the extremity of the lion's 

 tail, a small conical and slightly cui-ved claw, which is attached to the skin 

 only, and not to the last caudal vertebra: it is difficult to conjecture what can 

 be its use. 



