106 HANDBOOK OF INVERTEBRATE ZOOLOGY. 



h. During the next stage of activity, each of these 

 eight becomes divided into two, by a cleavage along a 

 plane passing through the principal axis. In a polar 

 view (Fig. 54), eight of the sixteen spherules thus formed 

 are visible, while ten are visible in a side view (Fig. 55). 



FIG. 51. FIG. 52. FIG. 53. 



FIG. 51. Side view of an egg at the end of the next period of ac- 

 tivity. (From a sketch by H. Carman.) 



FIG. 52. Similar view of the same* egg during the next period of 

 rest. ( From a sketch by H. Garman. ) 



FIG. 53. View of one of the poles of the principal axis of an egg, 

 at the commencement of the next period of activity. (From a sketch by 

 Mr. H. Garinan.) 



FIG. 54. FIG. 56. FIG. 56. 



FIG. 54. Similar view of the same egg at the end of the period of 

 activity. (From a sketch by Mr. H. Garman.) 



FIG. 55. Side view of the same egg. (From a sketch by Mr. H. 

 Garman.) 



FIG. 56. Surface view of an egg in an advanced stage of segmenta- 

 tion. (From a sketch by Mr. H. Garman. ) 



i. Repeated divisions increase the number and diminish 

 the size of the spherules, and in from three to twenty-four 



