No. 584] 



BILATERALITY IN VERTEBRATES 



515 



Explanation of Plates 

 Since no explanation of the figures could be found 

 other than those included in the preceding pages, I have 

 endeavored to give an explanation in accord with the 

 text. It should he remembered however that the figures 

 may be open to other interpretations than those pre- 

 sented. The figures show the distribution of pigment 

 and the relation of the embryo and the cleavage planes 

 to the pigment. It will be noted that the eggs when 

 viewed from above show a lighter area or crescent on 

 one side. This excentrie position of the pigment is like- 

 wise well shown in profile. The arrows in all cases show 

 the direction of the forthcoming embryo. 



