PHENOMENA OF INHERITANCE 285 



would be expected in only a small proportion 

 of the offspring. As a matter of fact it is 

 known that the children of mulattoes vary 

 considerably in color, and in some cases a child 

 may be darker or lighter than either parent, 

 which would indicate that segregation does 

 actually occur. It is very probable that this 

 classical case of "blending" inheritance is really 

 Mendelian inheritance in which two or more 

 factors for skin color are involved. 



Similar "blending" inheritance is found in 

 certain other cases where the parents differ in 

 form or size. Thus Castle found that when 

 long-eared rabbits were crossed with short- 

 eared ones the offspring have ears of inter- 

 mediate length, and in all subsequent gener- 

 ations the ear length remained intermediate 

 between that of the parents. He found the 

 same thing true of length and breadth of the 

 skull (Fig. 63) and of the size of other portions 

 of the skeleton, and he concluded that such 

 quantitative characters are not inherited in 

 Mendelian fashion. 



Quite recently MacDowell, working on the 

 inheritance of size in rabbits, concludes that 



