10 BENNET M. ALLEN 
The slightly greater number of sex-cells in the sex-glands of this 
specimen as compared with that in the previous ones is of little 
significance. It most certainly does not indicate that there has 
been any extensive division of them. In a previous work upon 
Chrysemys, (Allen ’07), it was shown that there was an extreme 
amount of individual variation in the number of sex-cells. This 
variation in Lepidosteus is relatively slight compared with that 
observed in Chrysemys. In a specimen slightly older than this 
stage (18 mm.) there were 171 sex-cells in the right sex-gland, 
and 173 in the left one, the total number, 344, being not far from 
the average. 
In these two stages, 17 and 18 mm., the sex-cells usually occur 
singly, although in places they are aggregated into clumps so 
thick as sometimes to show as many as five or six in a section 
of one of the sex-glands. Whether the sex-cells occur singly or 
in clumps, they are surrounded by peritoneal cells which con- 
tribute materially to the formation of the ridge-like anlage of 
the sex-gland. 
Lepidosteus 24 mm. total length. In aspecimen of this length, 
fig. 12, there is no essential advance in the development of the 
sex-gland. There were 147 sex-cells in the right sex-gland, and 
154 in the left one. The total number, 301, is distinctly below 
the average. 
Comparison with other forms leaves no room for doubt as to 
the identity of these sex-cells. Since the aim of this paper is 
merely to trace out their origin, we will not follow them through 
later stages in their history, but will describe the conditions found 
in a specimen 110 mm., in length, fig. 13. A complete series of 
sections through the sex-gland region of this specimen was not 
made, so it is impossible to give a full account as to the number of 
sex-cells and general condition of the sex-gland at this time. 
In running through the series one is struck with the sparseness 
of the sex-cells. Never are more than two or three to be found 
in a single section, and often none at all. This would lead one 
to infer that there has been little or no multiplication B the sex- 
cells even at this late stage of development. 
