PLATE II. 
Figure 10. — The same egg one minute later. The line be- 
tween the second micromere and macromere has disappeared, 
and the first micromere, c, now projects from one end of the 
elongated mass formed by the union of the spherules a and h. 
Figure 11.— The same egg three minutes later. The fusion 
of a and b is now complete, and a large transparent vesicle is 
now visible in the first micromere, c , and another in the com- 
pound mass, ah. 
Figure 12. — The same egg two minutes and thirty seconds 
later. 
Figure 13. — Another egg, about two minutes later. This 
is the true resting stage, at the end of the second period of 
rest. The two vesicles have become irregular. The remains 
of an external membrane adhere to one side of the egg. 
Figure 14. — The same egg seven minutes later than Figure 
13. The compound mass, a and Z>, is elongated, the first mi- 
cromere, g , is well defined, and waves travel from the nutri- 
tive towards the formative ends of the two masses. Two seg- 
mentation nuclei occupy the positions of the large vesicles of 
earlier stages. This stage is the beginning of the second pe- 
riod of activity. 
Figure 15. — The same egg one minute later. The second 
micromere, h , is now well defined, as well as the first. 
Figure 16. — The same egg one minute later. This stage 
marks the end of the second period of activity. The forma- 
tive end of the egg is now occupied by four micromeres, two 
of which seem to be the products of the division of the first 
micromere, c , and two of them the products of the second, h. 
Figure 17. — The same egg two minutes later, at the com- 
mencement of the third period of rest. The second micro- 
mere, h , lias again begun to fuse with the macromere, a. 
Figure 18. The same egg three minutes and thirty seconds 
later. The second micromere is no longer separated from the 
macromere, and mass, a and h , formed by their union is nearly 
spherical. 
