CONFIRMATIONS OF MEND ELS LAWS 361 



first hybrids is more or less influenced by the recessive character. 

 Polish fowls with a large hernia of the brain on the top of the 

 head were paired with Minorcas with normal heads. The 

 hybrids showed no hernia, but most of them showed a frontal 

 prominence. When the hybrids were inbred the hernia oc- 

 curred in 23-5% — a close approximation to the theoretical 25%. 



Single-combed black Minorcas were crossed with white-crested 

 black Polish fowls with a very small bifid comb. The hybrids 

 had combs single in front, split behind. When the hybrids were 

 inbred there resulted in a total of 101 offspring, 297% with 

 single combs (like Minorcas), 46*5% with Y-shaped combs, and 

 23*8% with no combs or only papillae (like the Polish forms). 

 Here, again, the result is in a general way Mendelian, but the 

 Y-like comb is a complication. 



Pigeons. — R. Staples-Browne crossed -a web-footed pigeon (an 

 occasional discontinuous variation) with a normal form, and got 

 six normal young. In other words, the web-foot character is 

 recessive to the normal foot character. The hybrids were 

 inbred, and in one case produced nine with normal feet and 

 three with webbed-feet — a Mendelian splitting-up But from 

 another pair of hybrids seventeen normal offspring resulted. 

 Thus, the illustration of Mendelian inheritance is inconclusive. 

 Besides, the numbers were too small. 



We have noticed elsewhere that crossing different breeds 

 of pigeons often results in forms which more or less resemble 

 the reputed original ancestor, the wild rock dove; in other 

 words, reversions occur. Often, however, the results seem quite 

 anomalous, which is probably due to the number of latent 

 characters which different races of pigeons appear to carry. 



Mice. — Mendelian phenomena have been carefully studied 

 in mice. Thus, when a grey mouse is paired with an albino, the 

 hybrid offspring are always grey. When these are inbred, they 

 yield greys and albinos, approximately in the proportion 3 : i, 

 Thus Cuenot obtained 198 greyr and 72 albinos. 



