170 Crossing the North and South African Ostrich 



Bateson, and also by Morgan, that new characters make their appearance 

 as a result of changes in the germ plasm, without any reference to external 

 influences, or any utilitarian value or need of the individual. Since the 

 baldness is now present as a duplex dominant in all the imported birds 

 it must have originated long ago in the history of the northern ostrich, 

 sufficiently long for the change to have affected all the individuals. For, 

 as will be shown later, there is good reason to suppose that in the ostrich 

 a new character appears at first in only a few members, but gradually 

 extends to more and more, by the continued change de novo in the germ 

 plasm of the nulliplex members of the race. 



The Egg. 



As in all other birds the eggs from the same ostrich and also from 

 different ostriches vary within certain limits, as regards size, shape and 

 surface characters. Beyond these fluctuating variations however certain 

 well-defined differences distinguish the egg of the North African from 

 that of the South Afi-ican bird (PL VII, fig. 3). 



Egg of North African Ostrich. The egg of the northern bird is 

 practically always larger than that of the southern, the shell is almost 

 free from obvious pores or pit tings, and presents an ivory-like smooth 

 surface. Usually also the northern Qgg is rounder in shape or less oval. 

 Measurements have been taken at the nest of the long and short dia- 

 meters of four series of eggs and are as follows, in inches : 



TABLE I. 



Measurements of Eggs of North African Ostrich. 

 Series A Series B 



