No. 614] 



THE BLUE AN DAL US I AN 



103 



the blacks the down is black with the exception of the ventral surface, 



in the white splashed it is of an exceedingly pale blue tint as a rule, 

 though sometimes practically colourless. 



The above figures bear out the view we previously expressed as to the 

 heterozygous nature of the blues, . . . 



The only other definite figures that have come under 

 the writer's notice are from W. J. Coates, a blue Anda- 

 lusian breeder of East Calais, Vermont, quoted by Piatt 

 (1916, p. 665) and referred to by Pearl (1917, p. 149). 

 These are for matings of blue to blue and are as follows: 



The fact that birds showing dark red appear is unusual 

 and would seem to indicate that the Coates stock differs 

 in its genetic constitution from the majority of the mem- 

 bers of the breed, unless the occasional appearance of red 

 is a fact usually suppressed by breeders. 



Bateson and his co-workers make no attempt beyond 

 that quoted above to account for the hereditary behavior 

 of Andalusians and appear content to rest the case on the 

 assumption that "blue is a heterozygote of black X 

 splashed white." 



The fact that 4 ' blue" is not a true intermediate be- 

 tween black and blue-splashed does not seem to have re- 

 ceived due consideration. While the blue-gray bird is in 

 a sense intermediate between self black and an individual 

 that approaches white more or less closely, this inter- 

 mediacy is more apparent than real. As previously 

 pointed out, it is not intermediate in regard to either of 

 the conditions involved when they are considered sepa- 



