174 Crossing the North and South African Ostrich 



intermediate as regards size, shape and the nature of the shell between 

 typical northern and southern eggs. Obvious pittings occur over the 

 shell, often more numerous towards the air-chamber end, but are never 

 so plentiful nor so deep as in the eggs from the southern bird. The egg 

 has neither the full size nor the roundness of the northern ostrich, but 

 is larger than the southern, and its general surface is more enamel-like. 

 Naturally variations occur in the eggs laid by different hens, and some- 

 times they approach those of the one parent more nearly and sometimes 

 those of the other. The degree of pitting and smoothness of the surface 

 of the shell do not admit of more than a general statement, but the 

 dimensions of 34 cross-bred eggs are available for comparison with those 

 of the northern and the southern eggs. 



The average long diameter of 34 cross-bred eggs is therefore 6*01 inches 

 and short diameter 5*06 inches, the difference between the two diameters 

 being 0'95. 



The measurements of the three series may be compared as follows : 



43 North African Eggs 



34 Cross-bred Eggs 



20 South African Eggs 



Though not elaborate enough for many purposes the results suffice to 

 indicate that as regards size and shape the cross-bred eggs are inter- 

 mediate between those of the northern and the southern bird. They 

 apparently approach somewhat nearer to the southern than the northern, 

 but with such variable objects as eggs an indication of this kind maybe 

 deemed of little value when only small numbers are available. 



The intermediate nature of the cross-bred eggs, as regards size, 

 shape and the nature of the surface, may be taken to suggest that the 

 different characteristics of the eggs of the two races of ostrich are de- 

 pendent upon separate factorial representation in the germ plasm, as in 

 the case of the dimensions and colours of the birds. Also the factors 

 are not alternatives, for in the hybrid Qgg no one character of the parents 

 is dominant or recessive to the other, but each strives, as it were, for 

 expression, the result being something midway between the two. 



The Wing Quills. 



In farming practice the number of plumes to the wing of the ostrich 

 is an important matter, though selective breeding has hitherto been 

 concerned with the quality of the plumes rather than with their quantity, 

 it having been assumed that not much variation in number occurs. The 



