92 W. M. Smallwood 
the change in the form of the chromosome. Here the irregularity 
seems to be an inherent quality of the chromatie material itself, 
independent of the chromosome vesicles (linin sheaths). 
I have counted the number of chromosomes in several eggs in 
each species and believe the number to be 16 during maturation 
and 32 in the segmentation stages. 
Before the second maturation figure is completed, the chromo- 
somes usually pass through interesting changes. During the late 
anaphase of the first maturation, the chromosomes lie erescent-like 
in the region of the deep centrosome (Figs. 6, 7, 8), but show no 
evidence so far as was observed of passing into a vesiculate state. 
At about the time that the young amphiaster of the second maturation 
figure is forming and moving into a radial position, a distinet mem- 
brane appears around each chromosome in many eggs (Figs. 9, 10). 
These ehromosome, vesieles lie so near the chromosomes as to be 
overlooked in many instances. It frequently happens that one chro- 
mosome vesiele contains two or more chromosomes (Fig. 9) in wbich 
case the chromosomes are united by narrow strands of chromatin. 
That the chromosomes do not always pass into chromosome 
vesicles and undergo these important changes is shown by the con- 
ditions in Fig. 11. Here the chromosomes lie free in the cytoplasm 
and it is believed by the writer that this is a perfeetly normal con- 
dition and that there may be two distinet processes in the maturation 
of these Nudibranchs just as there are in H/aminea (SMALLWOOD, 04). 
The process free from the containing vesieles is about the same as 
that which occeurs in most animals. The conclusion that there are 
these two rather distinet processes in maturation is not reached 
without studying a large number of eggs in both states and when 
it was found impossible to harmonize all of the conditions I was 
forced to arrange the phenomena under two heads. In describing 
similar changes in the egg of Haminea the following distinetion 
between the two processes was made. »T'he two processes occur 
with about the same frequeney, but all the eggs in one capsule 
follow either one method or the other. Any division of these pro- 
cesses into successive stages must be more or less arbitrary, espe- 
cially since there are no periods of rest, the changes being both 
continuous and rapid. Until the centriole at the deep end of the 
first maturation spindle has divided and the chromosomes of that 
spindle have begun to move apart there is nothing to indicate that 
there are two processes, except possibly a difference in the size of 
