PLATE XLIII. 



Abnormalities Found in Nature. 

 ly show effects of pressure ; figs. 6-8 ai 



of diluted sea water. 



Fig. 1. Immature egg probably incapable of maturation 



Fig. 2. 



near vegetal pole, containing sperm 



nucleus. 



Fig. 3. 



aing a sperm nucleus with sperm sphere attached 

 sperm nucleus ; the granular body near the aflimal 



egg nucleus 



Fig. 4. 



sperm nuclei normal but removed from animal 



pole; abnormal lobe at vegetal pole. 

 Fig. 5. Egg with abnormally 1 



6-8 



suppressed : two micromeres 



am 



Fig. 9. Two-cell stage with entire amphiaster in one cell, and no nucleus or centrosome in the 

 cell. Probably spindle was displaced by pressure, to one side of cleavage plane ; nevertheless egg has di 

 with formation of well marked "Zwischenkorper." 



Fig. 10. Two cells; chromosomes scattered around active centers; this would probably give i 



karyomeres in the resting stages. 



Fig. 11. 



(topped and the nuclei, spheres and cytopl 



normal positions 



Figs. 12, 13. Eggs with large lobe opposite end of spindle, result of pressure 



In 



has 



plane and is constricted by it. 



Fig. 14. Two-cell stage with gonomeres 



Fig. 15. 

 Fig. 16. 



with 

 tetraster 



Fig. 17. Four centrosomes, karyomeres, cleavage planes suppressed; the result, probably, of a 



tetraster. 



