146 



Degeneration in the Ostrich 



heterozygous, as would be expected from the mixed breeding hitherto 

 carried on and the wide variations represented, and the high numbers 

 are dominant over the low. Experiments to establish germinal purity 

 are however in progress. It is hoped to demonstrate that each suc- 

 cessional number of wing plumes represents a germinally pure line, that 

 is to say, that each plume has distinct factorial representation in the 

 germ plasm. Without doubt the variations already noted among the 

 coverts are also capable of extraction as numerically pure lines, but to 

 establish it experimentally would be a prolonged undertaking. If there- 

 fore the factorial individuality of the variations in the wing plumes can 

 be proved it may be admitted for the rows of coverts also and for the 

 feathers generally. 



The matter of genetic purity of the remiges has also an important 

 industrial application, for if established it becomes possible to provide the 

 ostrich farmer with a bird giving at least the high average of 44 plumes 

 to the wing in place of the degenerative average of 36 with which he 

 now farms, the coverts being increased in like proportion. As indicating 

 the likelihood of ultimate purity the series given below in Tables I — III 

 have been selected from a number of others of a like character. 



The above represents the best effort at present to establish a 

 numerically " pure strain " of ostriches from the highest numbered birds 

 available, and it must be admitted that the results are encouraging. 

 In both cases the parents have a mixed ancestry, having been reared 

 before the question of plumage number was under consideration. The 

 parental details of the South African cock are not available, while the 

 cross-bred hen is from a Cape cock having 42 plumes to the wing mated 



1 The high numerals are those given the adult birds in the ostrich register, the low 

 successiotial numbers apply to young chicks which usually do not receive their register 

 number until about six months old. 



