PLATE 2 



EXPLANATION OF FIGURES 



Hydractinia echinata 



14 Mature egg, showing the arrangement of mitochondria, simple and com- 

 pound yolk, and oil; diagrammatic. Symbols as in plate 1. X 2625. 



15 Types and development of compound yolk-spheres. X 2625. 



16 Mature egg as shown after staining with iron-hematoxylin. X 2625 



17 Young oocyte, showing radial arrangement of nuclear net. Meves' killing 

 fluid. X 825. 



18 to 20 Older eggs showing the gradual disappearance of the nuclear net in 

 a homogeneous ground-substance. Meves' killing fluid. X 600. 



21 Nucleus showing the complete disappearance of the nuclear net, a granular 

 ground-substance only remaining. Meves' killing fluid. X 600. 



22 The same, after sublimate-acetic killing fluid, showing a strong coagula- 

 tion net in a colorless ground-substance. X 600. 



238 



