496 
MONTGOMERY. 
[Vol. XV. 
we should expect to find the largest nucleoli in the smallest 
cells and the smallest ones in the largest cells. Further, the 
nucleolar substance cannot be regarded as a secretion of the 
nucleus itself, since this would leave unexplained the peripheral 
position which it at first occupies in the nucleus. Thus the 
mode of origin of the nucleolus in these cells would seem to be 
similar to that of the nucleoli in the ova of the nemerteans. 
A final point may be noted : the nucleolus accepts the same 
stains, though more intensely, than do the nutritive particles in 
the cytoplasm ; accordingly, the substance of those bodies which 
have been absorbed by the nucleus, and then by their fusion in 
the nucleus produce the nucleolus, must have undergone either 
a slight chemical or physical change within the nucleus. 
The largest mesenchym cells of the pseudoepithelia probably 
represent the youngest stages of the ova, though in the single 
individual of this species at my disposal no gonads were pres¬ 
ent, so that I can bring no proof positive that this is the mode 
of origin of the egg cells. In Carinella it is from similar cells 
that the genital products are derived, as I have previously 
shown (’ 96 ). Coe (’ 95 ) described certain of the more mature 
egg stages. 
In my earlier paper on these cells ( l.c .) I termed all the 
nuclear divisions of these cells “amitotic.” But renewed study 
of these elements shows that only the divisions of those cells 
are amitotic (Figs. 316a and 317), from which the free mesen¬ 
chym cells are produced. Whereas, in the nuclear divisions of 
the cells of the pseudoepithelia from which the masses of larger 
cells are derived I now find evidences of regularity in the 
distribution of the chromatin, so that probably these divisions 
are mitotic. However, in these small nuclear divisions it is 
almost impossible to decide whether we have to do with mitoses 
or with amitoses without the use of better lenses than those 
which were at my disposal. 
21. Ganglion Cells of Nemerteans. 
I may here briefly mention the relations of the nucleoli in 
these cells, and for other details refer to a previous contribution 
of mine (’ 97 ). 
