PLATE 7 



EXPLANATION OF FIGURE.S 



Eudendrium ramosiim 



54 and 55 Two stages of the first polar spindle. X 2625. 



56 Equatorial plate of first polar spindle, showing 3 chromosomes. X 2625. 



57 and 58 Two stages in the formation of the second polar body. X 2625 



59 The female germ nucleus. X 2625. 



60 Fertilization stages, showing the two germ-nuclei of equal size. X 2625. 



Hydractinia echinata 



61 Two centrifuged eggs showing the egg materials separated into three 

 layers. X 85. 



62 Section of a centrifuged egg showing the distribution of the cell-elements, 

 oil at the narrow end, a protoplasmic layer below, yolk and mitochondria at the 

 broad end. X 338. 



248 



