THE EVOLUTION OF MAN 



Fig. 10. — Primitive eggs of various animals, performing amoeboid move- 

 ments (very much enlarged). All primitive eggs are naked cells, capable of 

 change of form. Within the dark, finely granulated pi'otoplasm (egg-yelk) 

 lies a large vesicular kernel (the germ-vesicle), and in the latter is a 

 nucleolus (germ-spot) ; in the nucleolus a germ.point (nucleolinus) is often 

 visible. Fig. A 1 — A 4. The primitive egg of a Chalk Sponge (^Leucuhnis 

 echinus), in four consecutive conditions of motion. Fig. B 1 — B 8, The 

 primitive egg of a Hermit-crab (Chondracaiithus cornutus), in eight conse- 

 cutive conditions of motion (after E. van Beneden). Fig. C 1 — C 5. 

 Primitive egg of a Cat, in four different conditions of motion (after Pfluger). 

 Fig. D. Primitive egg of a Trout. Fig. E. Primitive 'egg of a Hen. Fig. 

 F, Primitive human egg. 



