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THE AMERICAN NATURALIST [Vol. XLV 



interest are the roan by roan matings, which produced 56 

 reds, 193 mixed color (i. e.,roan and red-and-white) and 

 60 white offspring. This does not fit well into the now 

 abandoned hypothesis that "roans are simplex, reds are 

 duplex and whites nulliplex." The number being quite 

 large should approximate more nearly the expected 50 

 per cent, of roans, or even less than 50 per cent., inasmuch 

 as some reds were later thought to be simplex ; however, 

 there are 62.46 per cent, roans. This may mean that some 

 roans are pure and when mated to like animals will pro- 

 duce only roans — as mating No. 1, wherein two roans 

 produce only roans, which in turn are pure and will re- 

 produce themselves. As further explanation in account- 

 ing for an excess of roans — which is common in most 

 herds— note that in matings Nos. 1, 2, 7, 8, 9, 19 and 45 a 

 roan mated with a roan produces roans only. As to the 

 red by red matings, types Xos. 6 and 15 will give only 

 red offspring, while type 30 gives 75 per cent, red and 25 

 per cent, roan, which fits very well the distribution — 133 

 red, 12 red-and-white, 34 roan and 1 white— with the 

 exception of the one white which will be discussed a little 

 further on. As a matter of fact, every possible color 

 mating has been reported to throw every other color 

 characteristic of the breed. 



The red Shorthorn calf of white parentage is no doubt 

 derived as follows: Save for occasional insignificant red 

 patches in the ears, many Park Cattle are solid dominant 

 white ; this element in a few cattle of the Shorthorn breed 

 would in the course of time, by the laws of chance, make 

 the mating Sets 1 and 2 (WwR 2 ), Sets 1 and 2 (WwR 2 ), 

 which would throw 25 per cent, red calves; this appar- 



more frequently possible white by white mating 



The red-by-red mating that produces a white calf is 



