PLATE XL1II. 

 Abnormalities Found in Nature. 



Figs. 2-5, 9, 11-13, 15 probably show effects of pressure; figs. 6-8 and 16 and 17 probably show effects 

 of diluted sea water. 



Fig. 1. Immature egg probably incapable of maturation; follicle cells attached. 



Fig. 2. First maturation division; abnormally large "yolk lobe" near vegetal pole, containing sperm 

 nucleus. 



Fig. 3. Enormous lobe at vegetal pole containing a sperm nucleus with sperm sphere attached; the 

 small nucleus on the right is probably an accessory sperm nucleus; the granular body near the animal pole 

 is probably the egg nucleus. 



Fig. 4. Egg probably distorted by pressure; egg and sperm nuclei normal but removed from animal 

 pole; abnormal lobe at vegetal pole. 



Fig. 5. Egg with abnormally large yolk lobe. 



Figs. 6-8. Eggs in which the 1st and 2d yolk cleavages were suppressed; two micromeres have been 

 formed at the animal pole; karyomeres are present; probably the result of diluted sea water. 



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

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

 with formation of well marked "Zwischenkorper." 



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

 karyomeres in the resting stages. 



Fig. 11. Egg in which the 1st cleavage has been stopped and the nuclei, spheres and cytoplasm are 

 out of their normal positions; probably the effect of pressure. 



Figs. 12, 13. Eggs with large lobe opposite end of spindle, result of pressure. In fig. 12, the gonomeres 

 are distinct; in fig. 13, the spindle has been pressed out of position and one of the nuclei lies in the cleavage 

 plane and is constricted by it. 



Fig. 14. Two-cell stage with gonomeres distinct. 



Fig. 15. Two cells, interkinesis, with cell lobes in spindle axes of 2d cleavage. 



Fig. 16. Two cells each with a tetraster. 



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

 tetraster. 



