52 



PROBLEMS OF GENETICS 



due to the excitation of dormant buds, for it is apparent on 

 examination that the new growths are not placed in any fixed 

 geometrical relation to the original plant. They arise on the 



Fig. 6. Two right hind feet of polydactyle cats. II shows the lowest de- 

 velopment of the condition yet recorded. The digit, d\, which stands as hallux is 

 fully formed and has three phalanges. Both it and the digit marked d% are formed 

 as left digits. In the normal hind foot of the cat the hallux is represented by a 

 rudiment only. 



J shows a further development of the condition. In this foot there are six 

 digits, di has two phalanges, but both it and d 2 and d 3 are shaped as left digits. 

 Thus d 3 , which in the normal foot would be shaped as a right digit, is transformed 

 so as to look like a left digit. 



petiole, for example, as small green outgrowths each of which 

 gradually becomes a tiny leaf. The attitude of these leaves is 

 quite indeterminate, and they may point in any direction, 



