No. 627] GERM. PLASM OF THE OSTRICH 329 



suffices to prove that this was the condition in the ances- 

 tral ostrich ; more usually eight to ten are missing and 

 also fail to appear in the progeny. It is therefore reason- 

 able to assume that the germ factors originally involved 

 in the production of the eight to ten under-coverts have 

 disappeared from the majority of ostriches though they 

 are retained in a few. The fact that all the intermediate 

 numbers can yet be obtained shows the loss to have been 

 progressive. A similar line of argument can be applied 

 all through. Loss or degeneration is in progress in vari- 

 ous directions and differs in degree in ditferent individ- 

 uals, and the losses are the outward expression of internal 

 changes in the germ plasm. 



Where a loss of factors is taking place it could hardly 

 be expected that all the individuals of the race would be 

 affected at one and the same time. The process would be 

 more rapid in some than in others, some would incur the 

 loss at one time and some at another, and the results from 

 crossing would need to be reckoned with. PTence we can 

 understand the great diversity of stages represented in 

 the ostrich where large numbers are available for exam- 

 ination. It may be hard to comjirelieiul liow in the first 

 instance germinal cliaimc- can lie In-ouulii about, but if 

 once effected, their repel it ion and coiitimiaiicc can reason- 

 ably be expected. Beginning witli one or a few birds it is 

 manifest that as the loss in any direction continues more 

 and more individuals will become affected, until in the 

 end complete loss for the race will be achieved. So far as 

 tlie investigation of farmer's troop?; has proceeded it 

 affords stnmg ovidt'iu'e for the view that oidy one orig- 

 inal 42-]^liinied l)iid iKuv exists in South Afriea. so that 

 under natural condition- the extinction of this high num- 

 ber of remiges would be imniiiient. The los> of the claw 

 from the third finger is ])rohably only recent. Some text- 

 books of zoology^ assert that a thii'd elaw oc<-urs. but it 

 has never been found on the hundred- of southern and 

 northern ostrich«»s coinitii; under my examination, al- 

 though speciallv UuAivd for. 



