CYTOPLASMIC INCLUSIONS OF THE GERM-CELLS. 603 
spheres. But not everywhere. Those parts where the mito- 
ohondria still seemed solid were generally seen to have their 
•cell elements slightly distorted or run together. I conclude 
that there is good evidence for believing that the mito- 
chondria of Helix consist of an inner, somewhat chromophobe 
substance, and a cortical stainable area. 
In Text-fig. 5 is drawn a diagrammatic scheme of the 
derivation of the various cell elements in the ovotestis from 
the indifferent epithelium. At S.P. 1 is the generation in 
which no spermatogonial divisions occur, the cell dropping 
into the lumen just when the growth stage has been entered. 
At S.P. 2 is a progerminative cell, which only divides once. 
Its elements may go on to the growth stage, or may (asatX.) 
divide again several times. At S.P. 3 the much-divided 
generation of spermatogonia is shown. At Y. the spermato- 
gonia are still dividing, and have become very small. Accord- 
ing as to the stage when the spermatogonial cells enter the 
growth period their cytoplasmic bodies have various more or 
less evident differences. The connecting link between S.P. 1 
and S.P. 3 is provided by such a cell as that in S.P. 2, whose 
divisions maybe curtailed. The diagram is based on evidence 
deduced from observation of the spermatogonia, but there is 
no manner of finding out how many times such a spermato- 
gonium as that at S.P. 3, Y, has divided. 
Below S.P. 3 are drawn the derivations of egg, yolk cell, 
and follicle cell from the epithelium. The latter is not 
proportionate in size to any of the cell elements in the figure. 
It has been shown that the number and size of the Neben- 
kern batonettes vary greatly. In some cases, such as the 
generation marked in PI. 29, fig. 1, by Roman numerals, the 
large number is never reduced by spermatogonial divisions, 
since these do not occur. The spermatocyte, therefore, has 
the original large number which appeared in the progermi- 
native cell. It seems certain that the individual batonettes 
do not increase in number before a spermatogonial division, 
so that after such a division their number is halved approxi- 
mately. 
