CROSSING THE NORTH AFRICAN AND SOUTH 

 AFRICAN OSTRICH. 



l^v J. E. DUERDEN, M.Sc, Ph.D., 



Professor of Zoology, Rhodes Universitij College, Grahamstown ; Officer- 

 iti-Charge, Ostrich Investigations, Groot/ontein School of Agriculture, 

 Middelburg, C. P., South Africa. 



(Wilh Plate Vn, ami Two Text-figures.) 

 CONTENTS. 



PAOE 



Introduction 156 



North African Ostrich 157 



South African Ostrich 157 



Nature of the Material . . 159 



Dimensions 162 



Colour 163 



Northern Ostrich 165 



Southern Ostrich 166 



Cross-bred Ostriches 166 



Bald Head.Patch 168 



The Egg 170 



Egg of North African Ostrich 170 



Egg of South African Ostrich 171 



Eggs from Cross-matings 172 



Eggs from Cross-bred Hens 173 



The Wing Quills 174 



North African Ostriches ....... 175 



South African Ostriches 176 



Cross-bred Ostriches 177 



Survival of 42-plumed Ostriches 178 



Scutellation of Middle Toe 181 



Claw on Fourth Toe 185 



Discussion 186 



Factorial Constitution , 18«3 



Adaptive Value of Changes 190 



Establishment of Characters 193 



Specific distinctness of Northern and Southern Ostrich . 196 

 Joarn. of Gen, vrii 11 



