BILATERALITY OF THE PIGEON S EGG 



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c.c. 



Diagram II Showing the development of the oocyte, and axial relations. A, 

 Primordial follicle of 50^ in side view showing the relations of long and polar axes; 

 B, the same in polar view, showing the relation of the long (ooplasmic) axis to 

 the nuclear axis; and the relation of the germinal vesicle to the long axis; C, Oocyte 

 of 0.6 mm. Beginning of period of differentiation. Side view. The germinal 

 vesicle is near the center of the oocyte but nearest the animal pole and nearer one 

 end of the long axis than the other. The spherule zone lies between the central 

 and peripheral protoplasm. D, Oocyte of 3.0 mm. End of period of differen- 

 tiation; side view. The germinal vesicle is at the periphery; the latebra has 

 appeared and is eccentric in position. The zone of peripheral protoplasm has 

 become narrow. ^, mature ovarianeggof 20 mm. End of the final growth period. 

 Side view showing the long and polar axes and the eccentricity of the latebra. 

 F, Oviducal egg in polar view showing the relation between long axis and the 

 embryonic axis as indicated by the shorter axis of the blastodisc. 



