REPRODUCTION. 



65 



acter than usual are going on in their molecular constitution ; 

 but, on the other hand, there may be really a diminution of 



Pio. 63.— Primitive eggs of varions animals, performing amceboid movements (very 

 mnch enlai;ged). All primitive eggs are naked cells, capable of change of form. 

 Within the dark, flnely granulated protoplasm (eeg-yelk) lies a large vesicular 

 kernel (the germ-vesicle), and in the latter is a nucleolus (germ-spot); in the nu- 

 cleolus a germ-point (nucleolus) is often visible. Fig. A 1 — A 4. The primitive 

 egg of a chalk sponge (LeuculmU echinus), in four consecutive conditions of mo- 

 tion. Fig. B 1—S 8. The primitive egg of a hcrmit-cr&b (Ohondracanthus eomu- 

 tvs). in eight consecutive conditions of motion (after E. Van Beneden). Fig. C 1 

 — OS. Primitive egg of a cat in four different conditions of motion (after PflBi 



Fig. D. Primitive egg of a trout. Fig. E. Primitive egg of a hen. 

 tivc human egg. (Haeckel.) 



(after Pflflger). 

 Fig. F. Pnmi- 



these activities in correspondence with the law of rhythm. This 

 seems the more probable. The meaning, however, of a " resting 

 6 



