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. Garman.) 



Fig. 52. — Similar view of tlie same* egg during the next period of 

 rest. (From a sketcli 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. Garman.) 



Fig. 54. Fig. 55. Fig. 56. 



Fig. 54. — Similar view of the same egg at tJie 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 



