BLENDING INHERITANCE 193 



dominants would be extremely unlikely, and it might 

 easily be mistaken for a mutation or a freak. Appar- 

 ent blends of all intermediate degrees, however, would 

 be sure to appear. Yet these are not blends in the 

 "melting-pot" sense at all, but strictly cases of Men- 

 delian dominance and segregation. 



9. THE APPLICATION OF THE NILSSON-EHLE EX- 

 PLANATION TO THE CASE OF RABBIT EAR- 

 LENGTH 



The so-called blending rabbit ears, along with 

 other similar cases, can now be made to fall into line, 

 as pointed out by Lang, with the Mendelian law of 

 segregation. 



If we assume that the long ear of the lop rabbit 

 has only three independent but equal determiners for 

 excess length, the case becomes one of Mendelian 

 trihybridism with cumulative factors, which works 

 out like Nilsson-Ehle's red-kerneled wheat in the 

 following manner: 



In general the average for full lop ear-length may 

 be placed at 220 mm. and for the ordinary short- 

 eared rabbit 1 at 100 mm. The difference, or the ex- 

 cess length of the lop ear, is 120 mm., which, according 

 to the trihybrid formula, corresponds to the six doses 

 of the character symbolized in the upper left-hand 

 square in Figure 55 by six large screw heads, three 



1 Not the Belgian hare, as cited in the illustration given in Figure 

 52. The Belgian hare has typically a somewhat longer ear than 

 the ordinary short-eared rabbit. 

 O 



