254 THE ZOOLOGIST. 



very generally an artificially produced race of bastards (an un- 

 staple race suggestive of and a precursor of the infertility of 

 more evoluted crossings), certain forms of which are continually 

 endeavouring to break back into the two parent types ; these 

 latter, indeed, being the only staple, true-breeding young of 

 these mongrels. For instance, in what is styled the roan 

 " hybrid " (in cattle), in the first mongrel generation, while all the 

 offspring are of mixed roan type, at the fourth generation the 

 mixed hybrids (roans) have decreased to 1 in 6 as against the 

 pure ancestral types (reds and whites), while in the fifth generation 

 they are 1 in 13, and in the sixth only 1 in 27, and so on. 

 Mendelism in this appears only to no more than touch on the 

 first signs, the fringe of evolution, and (to use a chemical simile) 

 while the extreme form of species, such as Dog and Fox, may be 

 looked upon as different chemical compounds, Mendelian new 

 species may be said in comparison to be no better than mere 

 mechanical mixtures ; while as regards the more distinct forms, 

 such as new wheats, as bred from two divergent natural types, 

 there appears only an artificial bastard race which, contrasted 

 with the naturally evoluted parents, can by no means be con- 

 sidered examples of evolution. 



Where do we find in Nature any example amongst mammals 

 of species thus evolving from any such process as the experi- 

 ments of Mendel ? We cannot definitely say. Take that 

 gradually merging group, the Antelopes. Where is the Mendelian 

 new form ? Possibly only in the mongrel Cobus at the Zoo, and 

 this perhaps not a true " Mendelian " hybrid. Moreover, those 

 races which lend themselves to Mendelian experiment are chiefly 

 those that (as shown by certain biologists) are deficient in some 

 natural character. Thus the albino Mouse or Eabbit is 

 deficient in colour, the dwarf pea is deficient in size, and so on. 

 And thus, instead of the dominant and recessive characters of 

 Mendel shown by diagram to be as follows : — 



RK + DD = 2RDand 



R + 



D + 



