Xo. ()20] SIIOETER ABTK LK>, A\D COlUiK.srOX ( L 557 



occur in the genus, Cavia, except in the case of a single individual 

 born in one of our experiments. As this individual was still- 

 born we had no chance to experiment further in the case, but the 

 occurrence shows that degenerating characters are not of uoees- 

 sity lost for all time when they have ceased to have somatic ex- 

 pression in the race. 1 am therefore hopeful that Duerdeu will 

 live to see not only other 42-plumed ostriches but also those which 

 are 45-plumed or possibly even better, if selection for high num- 

 ber of plumes and inbreeding are persistently practised. 



One point is worth noticing, which Duerden does not especially 

 emphasize, though it is highly suggestive. He notes the advanced 

 state of degeneration of the ostrich foot (presumably through 

 irrecoverable loss of factors) as seen in the complete disappear- 

 ance of digits 1, 2 and 5, and the greatly reduced size of digit 4, 

 which leaves the ostrich with practically a single functional toe 

 (digit 3), this being among birds an unparalleled amount of 

 digital reduction. He concludes "Should the loss of plumage 

 continue to a much further degree and marked degenerative 

 changes be set up in thebiji' middle toe. natural seK'ction may then 

 be expected to brinu' ahout cWun-tum. ' This, it seems to me, is 

 a needlessly gloomy vu-w ,.f thr i-asc. The fact that the middle 



