2S8 STUDIES IN THE EVOLUTION OF ANIMALS 



which gave the ancestral forms pre-eminence, and enabled them to 

 stamp this feature on millions of descendants, but some other 

 anatomical and physiological characters, developing concurrently 

 with the five-digited hand and foot, which enabled that type to 

 endure and fight its way to our times. Four, three, two, and 

 perhaps even one digit were enough to secure survival. It would 

 seem that it was. not so much the limbs as the brain and viscera 

 which gained the day, in spite of the diminishing number of 

 digits. 



It seems impossible to account for atrophy of one or more 

 bones, which may sometimes occur all of a sudden, and give rise 

 to what is called an anomaly. If the abnormality or monstrosity 

 should happen to be useful, or can suit itself to surrounding con- 

 ditions, it may endure, and be reproduced, and possibly lay the 

 foundation of what might subsequently be called a normality. As 

 an abnormality, the animal may have originally been better off in 

 the struggle for existence. Certainly the struggle must be more 

 keen among those who have exactly the same structure. 



I remember seeing in Jeypore, Rajpootana, an adult who had 

 no arms at all. In what corresponded to the glenoid cavity of the 

 scapula there was a small finger, or at least what looked like one. 



Here then was a case not merely of atrophy of four digits 

 with their metacarpal and carpal bones, but suppression of the 

 whole radius, ulna, humerus, etc. Of course, such a monstrosity as 

 this was anything but useful, and not likely to endure. 



On the occasion that Professor M'Fadyean showed me the case 

 of cloven foot in a Horse, in the Journal of Comparative Pathology 

 and Therapeutics, already mentioned, he remarked that the phe- 

 nomenon was not very uncommon. The abnormality he showed 

 me was in a Horse four years old, and in only one foot. 



The Professor did not seem to look upon this anomaly as a 



