PLASMA-STRUCTURE IN EGG OF HYDRACTINIA 231 



9. The mitochondria and chromidia (extra-nuclear granules) 

 are not identical in Hydractinia. 



10. The mitochondria are not a vital part of the protoplasm 

 in Hydractinia but are a highly differentiated product. 



11. Maturation and fertilization are typical in Hydractinia 

 and Eudendrium and cleavage is mitotic. 



