FREE BOOKS

Author's List




PREV.   NEXT  
|<   41   42   43   44   45   46   47   48   49   50   51   52   53   54   55   56   57   58   59   60   61   62   63   64   65  
66   67   68   69   70   71   72   73   74   75   76   77   78   79   80   81   82   83   84   85   86   87   88   89   90   >>   >|  
een tried which in the end have proved most successful, giving us animals with the speediest movements of any animals except the creatures of the air. [Illustration: A Hunter] The success which has been attained in our ordinary large herbivora, and which has made them competent to evade the chase of the beasts of prey, has been accomplished by reducing the number of the toes, giving the strength of the aborted parts to increase the power of those remaining. The result is the formation of two great groups, the double-hoofed forms, including the pigs, deer, cattle, sheep, and their kindred, and the single-toed species, of which our horse is the foremost example. In the reduction of the number of toes, different plans were followed in each of these groups. In the cloven-hoofed forms, a single toe first disappeared, leaving but four; then the two outer of these were aborted, leaving two nearly equal digits. In the series of the horse, where we can trace the change more clearly, we find the earliest form five-toed, but the outer and inner digit shrunken so as to become of little use. This condition of the creature in the early Tertiaries gives us the beginning of the equine series, and shows that far away as the creature is now from ourselves, it originated from the main stem of mammalian life, from which our own forms have sprung. In the next higher stage in time, and likewise in development, we find these lessened toes at their vanishing point, and two of the remaining digits, lying on either side of what corresponds to the middle finger in our own hands, beginning to shrink in length and volume, while the central toe becomes larger and stronger than before. Last in the series we come to our ordinary equine form, in which nothing is left but the single massive extremity, though the remnants of two of the toes can be traced in the form of slender bones known as splints, which are altogether enclosed within the skin which wraps the region about the fetlock joints. As if it were to show to us the history of this marvellous organic achievement, nature now and then, though seldom--perhaps not oftener than one in ten million instances--sends forth a horse with three hoofs to each leg. Two of these are small and lie on either side of the functioning extremity. Each of these hoofs is connected with a splint-bone which has in some way suddenly become reminded of its ancient use, and develops in a manner to imitate the creature
PREV.   NEXT  
|<   41   42   43   44   45   46   47   48   49   50   51   52   53   54   55   56   57   58   59   60   61   62   63   64   65  
66   67   68   69   70   71   72   73   74   75   76   77   78   79   80   81   82   83   84   85   86   87   88   89   90   >>   >|  



Top keywords:

series

 

creature

 
single
 

leaving

 

groups

 

hoofed

 

extremity

 
remaining
 

digits

 

equine


beginning

 

ordinary

 

number

 
giving
 
animals
 

aborted

 

massive

 
develops
 

proved

 

remnants


altogether
 

enclosed

 
ancient
 

splints

 

traced

 

slender

 

stronger

 

larger

 

successful

 
manner

imitate

 

vanishing

 

corresponds

 
middle
 

central

 
volume
 
length
 

finger

 

shrink

 
million

instances

 
splint
 
connected
 

reminded

 

functioning

 

oftener

 

joints

 
fetlock
 
lessened
 

region