176 



THEORY OF E\'OLUTION 



limits of the race of fantail grandparents had 

 not a selected (surviving) lot loeen taken for 

 the figures gi^'en in the tahle. 



The preceding account attempts to ^Joint out 

 liow I should prefer to interjjret the problem 

 of selection in the light of the most recent work 

 on breeding. But I would gi^'e a very incom- 

 plete account of the whole situation if I neg- 

 lected to include some important work which 

 has led some of my fellow-workers to a very 

 different conclusion. 



Castle in 2)articular is the champion of a 

 view based on his results with hooded rats. 



Fto. 88. Hcheiiic to kIkhv chis.scs of hooded rats used by 

 Castle. (After Castle.) 



Starting with individuals which have a narrow 

 black stripe down the back he selected for a 

 narrower stripe in one direction and for a 



