148 



BIOLOGICAL LECTURES. 

 3 



Fig. VI. 



upon a mirror fastened to the stage of a dissecting microscope. 

 We could thus observe the changes occurring on opposite sides 

 of the egg without disturbing its position. 



The elongated form of the ^gg of Ainia, in a closely applied 

 envelope, prevents rotation about its minor axes. It is, there- 

 fore, a favorable Qgg for ascertaining Mrhat effects, if any, 

 gravity may have on the direction of cleavage, and for deter- 



