24 
W. E. AGAR. 
many of these nuclei will be found, still, they are much too 
rare to admit of the possibility of their being a normal stage 
in the prophase. I have not been able to determine whether 
a nucleus which has gone so far as that shown in PI. 5, fig. 35 
is capable of resuming mitosis, or whether it is destined to 
degenerate, but the balance of evidence is in favour of their 
re-entering the normal life-cycle of the spermatocyte by a 
disappearance of the nuclear membrane and a return to the 
condition shown in PI. 3, fig. 24. In any case, the inter- 
calation into the meiotic diakinesis of a resting or semi- 
resting condition of the nucleus with the somatic number of 
chromosomes is very remarkable. 
In the spermatogonia the nucleus may also occasionally 
enter into a corresponding semi-resting stage in diakinesis. 
Part of such a nucleus (belonging to a large spermatogonium) 
is shown in PL 5, fig. 36. This cell was in a young male 
whose testis contained very few spermatocytes, and there 
were none of these in the neighbourhood of this cell, so there 
is no doubt of its being spermatogonial. In any case similar 
nuclei are frequently found, which from their position and 
small size must belong to the smaller generations of sperma- 
togonia. The resemblance with the corresponding stage in 
the meiotic prophase is striking. As in the case of the 
spermatocytes, these nuclei are far too rare to be a normal 
stage in the spermatogonial prophase. 
Except for the dissociation of the chromosomes, the semi- 
resting stage just described puts one in mind of the “ germinal 
vesicle” stage of the oocyte, and it is a very interesting fact 
that in one testis several spermatocytes have at this 
stage actually taken on the character of oocytes. 
This testis came from a specimen dug out of the ground in 
the hibernating condition. About 11 mm. of the testis was 
sectioned, and within this length there are three undoubted 
eggs, with all the essential characteristics, both of nucleus 
and cytoplasm, of true ovarian eggs at an early stage of the 
growth period. The average diameter in ju of the ceil body 
and nucleus in each of the three is as follows : 200 and 84, 
