STUDIES IN CYTOLOGY 395 
ment. In addition this conclusion is practically the only one 
which can be reached in view of the now well established fact of 
the doubling of the number of chromosomes during monaster 
formation. 
Fig. 2 would be difficult to interpret, were it considered on its 
own merits alone. The long rod in each anaphase plate is evident 
The V’s appear here simply as thickened rods; 19 chromosomes 
are shown in each plate. Fig. 3 shows a similar state of affairs. 
Fig. 4 is similar with the exception that the V’s in 4 A are evident 
as such. . 
The description for these figures may be taken as typical of the 
large number studied in which the chromosomes could be made out 
clearly. I must also state that in my preparations, representing 
sixteen very successful chemical fertilizations, the number of 
abmodal chromosomes is very high. There is nothing like the 
almost uniformly even and regular series of division figures that 
may be seen in sections of normally fertilized eggs, nor do the 
figures approach in regularity those which I obtained from the 
artificially parthenogenetic starfish egg in 1906. The evi- 
dence here seems to be a confirmation of the statement made by 
Nemec (’11) that the form of the chromosomes may be changed 
by reagents although the processes of mitosis may be unmodified. 
B. Fertilized enucleated egg fragments 
The eggs were broken into fragments by being shaken in a test 
tube with broken bits of cover glass. For one series this mass was 
turned out in a flat dish and enucleated fragments picked out under 
the microscope with a pipette. The fragments were then fer- 
tilized with Toxopneustes sperm. Fertilization membranes were 
formed. The tempo of cleavage was the same as in eggs with a 
nucleus. Other series were prepared by shaking the eggs into 
fragments as above noted and fertilizing all of the fragments. In 
these the distinction between fragments with the double number 
of chromosomes and those with the half number is easily seen. 
The study of fresh material stained with Schneider’s aceto-carmine 
did not give especially useful results. 
THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 12, No. 3 
