No. 3-] THE EMBRYOLOGY OF A TERMITE. 515 



posterior pole this area is slightly more crowded than near 

 the shorter diameter ; but there is very evident activity here, 

 contrasting sharply with the inertia of the cells on the anterior 

 side of the line. 



Drawing a similar line across the middle of the older egg 

 (PI. XXIX, Fig. 11), we find no change anterior to the line. 

 In the region just posterior to this line, extending as far back 

 toward the pole as a second line drawn parallel through the 

 anterior end of the dotted pointer ca., there are fewer nuclei 

 than in a corresponding region of the younger Q.gg (PI. XXIX, 

 Fig. 10) — by actual count, nearly one-third less than in the 

 earlier stage, or 26 to 36 nuclei. On the other hand, in area 

 ca., PI. XXIX, Fig. II, a decided increase in the number of 

 cells is evident, as compared with the preceding stage. The 

 nuclei here are not only one-third more numerous (about 10 1 

 to 157), but are much more closely crowded together. 



Such a comparison indicates strongly that, in addition to a 

 special activity in cell division within the area ca. of PI. XXIX, 

 Fig. II, certain cells have actually wandered into this area from 

 more anterior portions of the surface. 



If the number of cells in the region anterior to ca., down to 

 the line through the shorter diameter, had remained the same 

 as in the preceding younger stage (PI. XXIX, Fig. 10), there 

 would have been reason to conclude that this constant number 

 had been maintained, in spite of a multiplication of cells, by a 

 migration back into ca. One-half of the product of the divi- 

 sions of the nuclei might have wandered back into ca. from the 

 more anterior region, without disturbing the relations existing 

 in PI. XXIX, Fig. 10. As it is, the evidence of a migration 

 back into the area ca. is much stronger, since an actual decrease 

 in the number of nuclei anterior to ca. has been shown ; while 

 the increase in the cells of ca. is sufficient to allow for this addi- 

 tion from without, as well as for that from a multiplication of 

 the cells already within its limits. 



Similar results are obtained from a comparison of dorsal 

 surfaces. 



It may be claimed that this method is inconclusive, since the 

 specimen from wnich PI. XXIX, Fig. 11, was drawn cannot be 



