73*; 



THE AMERICAN NATURALIST [Vol. XLV 



simple four-part Mendelian ratios in 42 case matings out 

 of 45, the exceptions being matings 28, 29 and 36. In sum- 

 ming up the coat-color inheritance of blue-gray cattle, 

 Barrington and Pearson say on page 435, "It will need a 

 complex allelomorph to describe these color changes, if, 

 indeed they can be described at all. ' ' With this it must be 

 agreed. The "complex" allelomorph is, however, not so 

 complex, after all; the complex is simply a group of 



similar units each independently transmitted. If they 

 were less uniform in their somatic aspects they would 

 not be so confused. The task of segregating the unit 

 becomes more difficult but not at all impossible. 



Barrington and Pearson emphasize the statement that 

 the evidence of the breeders of the blue-grays is that a 

 white Shorthorn bull of white parentage is greatly to be 

 preferred to one of roan parentage, inasmuch as the 

 former type invariably gives the desired blue-gray color 

 — referring to Mr. deVere Irving : 



