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THE AMEBIC AN NATURALIST [Vol. XLVII 



instead of behaving as separate "units" combined by indiscrim- 

 inate alternative transmission. Even the more complete rever- 

 sions to the parental types may be considered as results of non- 

 Mendelian coherence of characters in expression, rather than as 

 examples of Mendelian segregation and recombination of inde- 



COMPARISON OF BOVINE HYBRIDS WITH COTTON HYBRIDS 



The practical question to be determined is whether the Dur- 

 ham-like and Brahma-like individuals of the second and later 

 generations are equal to the original parental varieties, and 

 whether the intermediate individuals maintain the average of the 

 first generation. In the second generation of interspecific cotton 

 hybrids it is usual to find many degenerate plants with an ob- 

 vious resemblance to one or the other of the parental stocks, 

 though usually abnormal and inferior. But among the cattle the 

 second generation hybrids seemed much less different from the 

 first generation, both in constitution and in external features. 

 No general tendency to inferiority in the second generation, as 

 compared with the first, either in vigor or in resistance to ticks, 

 had been detected by Mr. Borden. But the experiments have 

 not continued long enough to afford adequate evidence on this 



If the analogy of cotton should be found to apply with the 

 bovine hybrids the Brahma-like and Durham-like animals that 

 appear in the second and later generations will not prove to be 

 equal to the Brahmas and Durhams that have not been hybrid- 

 ized, nor will the intermediate individuals show as high an aver- 

 age as the first generation. One of the usual results of crossing, 

 even among varieties of the same species, is to destroy the ef- 

 fects of previous selection in establishing a uniform expression 

 of the characters of the parent varieties. The fact that many of 

 the second generation of Brahma hybrids are magnificent ani- 

 mals does not prove that equally superior hybrid varieties can 

 be established. To increase the pure stock of Brahma cattle, and 

 thus increase the possibilities of producing first generation hy- 



5 In a more recent paper Dr. Xabours has recognized t'ae divergence from 



bilities of a New Breed of Cattle for the South", in American Breeders 

 Magazine, 4: 45, March, 1913. 



