358 THE CARNIVORES 



line, whereas in other Carnivores the second pair of these teeth is thrust up above 

 the level of those on either side. 



The fore-feet of all the cats are provided with five toes each, whereas the hind- 

 feet have but four toes. The claws in which these toes terminate are invariably 

 curved and sharp, and with the single exception of the hunting-leopard, can be 

 completely retracted within sheaths for their protection when not in use. The 

 mechanism of the retraction of the claws is due to the peculiar shape of the terminal 

 joints of the toes, and the mode by which they are articulated to the second joints. 

 Thus the terminal joint of each toe has the broad sickle-like form of the horny 

 claw which it supports, and it is articulated to the end of the second or preceding 

 joint only by the lower portion of its vertically expanded base. From the end of 

 the second joint there runs a ligament to be inserted on the upper side of the base 

 of the terminal joint, the ordinary action of which is to draw back the whole claw 

 upon the upper surface of the second joint, when it becomes nearly concealed within 

 its projecting sheath. To the under side of the base of the terminal joint there is, 

 however, inserted the end of a long tendon coming from one of the so-called flexor 

 muscles of the fore-leg. When the animal springs upon its prey the paw, in the act 

 of striking, is sharply bent upon the wrist by the action of these flexor muscles, the 

 result of which is to pull downwards the terminal joints of the toes, and thus to 

 fully expose the claws. In order to keep their claws in good condition, most cats 

 from the tiger downwards to the domestic cat are in the habit of drawing them 

 down the bark of trees, whereby they are rendered sharp and clean. 



All the species of cats walk; solely upon their toes, and are hence termed digi- 

 tigrade ; the hinder part of the foot being entirely raised from the ground to form a 

 continuation of the leg. This mode of progression indicates a higher special- 

 ization than the so-called plantigrade mode of walking in which, as exemplified by 

 the bears, the whole of the sole of the foot is applied to the ground. Formerly 

 the distinction between digitigrade and plantigrade Carnivores was regarded as 

 an important one in classification, but it is now known that nearly allied groups 

 vary greatly in this respect, and that the characteristic is a purely adaptive one. 

 It has been already mentioned that the fore-feet of the cats are furnished with five 

 toes. The innermost toe, corresponding to the human thumb is, hffwever, placed 

 at a much higher level than the other four toes, and is consequently of no use in 

 walking. The missing toe in the hind-foot corresponds to the human great toe. 

 The stealthy walk characteristic of all the cats is due to the soft cushions, or pads, 

 on the under surface of the feet ; each toe having a separate pad, behind which is a 

 large pad occupying the middle of the sole of the foot. The fore-foot is thus fur- 

 nished with six, and the hind-foot with five footpads. There is, however, on the 

 fore-limb an additional pad on the outer side of the palmar aspect of the metacarpus. 

 The impression, or spoor, of a cat's foot always shows the form and number of the 

 pads, and it should be particularly noticed that in such impressions there is no mark 

 of the claws, which in walking are completely retracted. This affords a ready means 

 of distinguishing between the track of a cat and a dog. 



In order to enable them to lick off the meat from the bones, and perhaps also 

 to aid in cleaning their beautiful fur, the tongues of all the cats are furnished with 



