178 NATURAL SCIENCE. Marcu, 
condition the convolutions of the beaded thread have again distributed 
themselves over each divided nucleus, and soon enlargement and 
total separation take place, as in Fig. 18. 
In the divided organism containing this organism the division- 
line soon again appears in the nucleus, and successive fissions go on. 
But in the nuclei belonging to the condition of special fissipartition 
shown in Fig. 7, the nuclei present quite a distinct appearance. No 
wall is at all discernible in connection with it, and it is slightly larger 
than the ordinary form; it is highly refractive, and, on critical exami- 
nation, does not show the exquisitely fine convoluted beaded thread 
of the usual nucleus, but dissociated white, and slightly darker, some- 
what oblong granulations, as shown in Fig. 19. When in the usual 
order, in the act of fusion shown in Fig. g, L, this nucleus comes into 
contact with the ordinary one (y, 6), there is almost immediate 
‘‘melting of either into other,” the whole mass resulting being milky 
and almost opaque, taking a white star-like appearance, resulting 
apparently from the diffusion of the whole mass through the entire 
plasm of the fused organisms, for in the course of a short time it 
disappears, and, asin Fig. 11, N, a non-nuclear triangular body results. 
The bodies ultimately emitted from this are of extreme minute- 
ness, and partially opaque; and in their growth one of the most 
remarkable features appear. 
In Fig. 21, if g represent the original spores as sent out into the 
fluid, p will represent their growth in form and relative size in an 
hour, 7 shows one of the same in an hour-and-a-half, while 7 (Fig. 22) 
gives the result of growth at the end of nearly three hours; but now 
very little advance in size is made; there is a pause, as if the form 
had been arrested in growth by death. But, on critical examination, 
there is found to be a very slight enlargement taking place, and with 
it the formation of the internal beaded thread-like convolution which 
may take thirty to fifty minutes to complete, as in Fig. 22, K. 
From this time growth is rapid; but it appears to proceed from 
within the nucleus outward, as shown in Fig. 23, where a small part 
of the body-substance has arisen outside the nucleus, , and, at this 
stage, the two flagella are seen as though emerging from the nucleus, 
as at/,m. The body-substance now rapidly grows until the adult 
form and size are reached, as in Fig 1, A, when the processes of the 
life-history once more repeat themselves. 
It would thus appear that every point in the cyclic changes in 
this organism originate in, or are initiated by, the nucleus. Fission 
is not only indicated, but begins first in the nucleus, while the nuclear 
changes during fission are worthy of careful note. The change in 
the character of the nucleus in certain forms after fission is full of 
suggestion, and that their subsequent union with nuclei of the 
common type is equivalent to fertilisation, we can scarcely doubt. 
Not less interesting is the origin of the nucleus in the growing form, 
and its relation to the growth of the body. 
