HANDS AND FEET. 889 



the feet are applied together, and the digits, which are webbed, 

 more or less divaricated. In order to fit them for their purpose 

 their proportions are very different from those of any foot which I 

 have yet described. It is the first and fifth digits (the great and 

 little toes of our feet) which are the largest and longest, while 

 the middle toe is considerably the shortest. The hand is fitted 

 to act as another kind of fin by a different modification. In it, 

 it is the pollex which is the largest and longest, and thence the 

 digits regularly decrease in size to the fifth, which answers to 

 our little finger. 



In Porpoises and Dolphins there are no feet at all, and an 

 expansion of skin and fat only answers the swimming purpose of 

 the feet of the Seal. The hand is made still more completely into 

 a mere fin than is the hand of the Dolphin, its digits being all 

 bound together in a tough and continuous investment ; whereas, 

 however, in the Seals the number of the phalanges, so constant 

 hitherto, remains the same as in man ; in the Dolphins they are 

 augmented, those of the index finger being as many as ten or 

 even fourteen in number. 



A very curious modification of both hands and feet is met 

 with in the Sloths. The digits are reduced in number to three, 

 or even to two, and are singularly rigid, being bound together by 

 membrane and skin down to the enormously long, strong, and 

 hooked claws. The arrangement of the parts is such that when 

 at rest they are bent over, as our hands are when our fingers are 

 flexed. In the Sloths it requires a positive effort to open, and, 

 as it were, unhook them ; and this condition is one of the greatest 

 utility to these animals, for Sloths pass their lives suspended 

 from the branches of trees, on the leaves of which they feed. 

 Moreover, they not only range about and feed in this position, — 

 hanging back downwards — but may also sleep in the same 

 posture. There is, however, no fear of their falling ; if shot at 

 and killed, they will still hang till they rot without falling, on 

 account of this j)ermanently flexed condition of their hook-like 

 extremities. 



In creatures which are not so very remotely allied to the 

 Sloths— I mean the Ant-eaters and Armadillos— very great 

 inequality may be found in the size of the different digits. In 

 the Great Ant-eater, which uses the claws of its powerful fore 

 limbs to tear down the nests of Termites, the creature walks 



