SEX-CELLS OF AMIA AND LEPIDOSTEUS 23 
total absence of any indication of degeneration of sex-cells in these 
or earlier stages, I feel convinced that this small number does not 
indicate any tendency to degeneration of sex-cells. 
Amia, 23.7 mm. total length. In the next stage studied, 23.7 
mm., the sex-cells numbered 102. Here again there is no evidence 
of a change in the number of sex-cells originally present. The 
number, although somewhat high, is exceeded by some of the 
specimens of very much earlier stages. There is no evidence of 
sex-cell division nor of any degeneration. 
Amia, 40 mm. total length. At this stage the sex-gland is 
elongated oval in transverse section. It has become bent over 
in such a way that the proximal edge is medial and the free edge 
TABLE 5 
Dimensions of sex-cells of Amia 
STAGE NUCLEUS CELL BODY 
Hours 
137 | 7.10 18.03 
147 | 6.71 18.70 
mm. 
3.7 | 6.45 21.88 
5.0 6.51 17.80 
9.1 8.00 14.96 
11.4 | 7.48 11.59 
15.0 7.48 12.64 
16.0 7.74 14.06 
23.0 | 7.22 14.20 
lateral in position. The mesodermal cells have increased greatly 
in number. The peripheral cells have become arranged into a 
somewhat poorly defined layer, while the sex-cells le in the in- 
terior of the sex-gland. No attempt was made to determine the 
time at which the sex-cells begin to divide, or to study the further, 
development of the sex-glands. 
Measurements of the nuclei and cell bodies of the sex-cells 
gave the following averages, two diameters being measured in 
each of five sex-cells chosen at random in each stage. 
Although the number of cells measured in each stage is hardly 
sufficient to justify one in considering these average dimensions 
