470 
two organisms. Here then is something entirely 
novel in the make-up of macro- and micronuclei, the 
micronucleus being absorbed and protected by the 
macronucleus. The size statistics of conjugating 
and non-conjugating forms are similar in essence 
to those of Paramecium. Miss Watters has meas- 
used some 1,580 specimens, of which 482 were 
conjugating. The average size of the conjugants 
is 110, of non-conjugants 140, the latter in- 
cluding exconjugants which never regain normal 
size. More than 150 exconjugants have been iso- 
lated and maintained from time to time. Not one 
has lived more than 16 days, the dates being 
22 per cent. dead on first day, 31 per cent. on 
second, 13 per cent. on third and 8 per cent. on 
fourth, with the rest scattering one or two per day 
until the sixteenth. This is similar to Biitschli’s 
results with Blepharisma in 1876, when all of the 
ex-conjugants died within three days after sepa- 
rating. Vitality therefore is not restored by con- 
jugation under the conditions of the experiments; 
whether it is due to these conditions, due to the 
pedogamic nature, or due to some other cause 
remains to be shown. 
It is expected that this paper will be published 
in full in the Journal of Morphology. 
Actinobolus radians St. and its Cultivation: GARY 
N. CaLKIns, Columbia University. 
Regeneration in Paramecium caudatum: FLORENCE 
PEEBLES, Bryn Mawr College. 
The results of a series of experiments on Para- 
mecium caudatum show that the power of regen- 
eration varies greatly in different races, and also 
in individuals of the same race. It usually de- 
pends on the condition of the protoplasm, or the 
age of the individual at the time of the operation. 
The removal of the anterior one third causes 
greater disturbance in the cell than the removal 
of the posterior end. The fragment which is 
removed always dies, but the larger nucleated 
piece either regenerates the lost end or divides 
without regeneration into a normal and an abnor- 
mal individual. Regeneration of the anterior end 
took place in forty per cent. of the cells, while the 
posterior end regenerated in sixty-three per cent. 
Cells in the vegetative condition when cut in half 
form no abnormal individuals. One half dies and 
the other produces a normal thce. It was found 
impossible by removal of the protoplasm to pro- 
duce a small race from a large one. After several 
generations the normal size was restored. Vegeta- 
tive cells seem to have much division energy stored 
up within them. Experiments indicate that three 
SCIENCE 
[N.S. Vou. XXXV. No. 899 
division planes are present, so that one cell repre- 
sents four individuals. The removal of a part of 
the protoplasm acts as a stimulus, and several 
divisions follow in quick succession. It was found 
impossible to cut the macronucleus in vegetative 
cells so that each fragment contained a part of it. 
When cells were cut in half during division both 
pieces received a fragment of the nucleus and 
formed normal races. 
It is expected that this paper will be published 
in full in the Biological Bulletin. 
Observations on Synapsis and Reduction: EpMUND 
B. WILson, Columbia University. 
The maturation-phenomena in Tomopteris and 
Batracoseps have been reexamined by a study of 
the original preparations of the Schreiners and of 
Janssens, as well as of new preparations of Ba- 
tracoseps fixed and stained by various methods. 
This study has led to a confirmation of the main 
conclusions of the above-named observers in regard 
to synapsis. The seriation of the stages is placed 
beyond doubt by the conditions seen in Batraco- 
seps. In both this form and Tomopteris the facts 
seem to admit of no other interpretation than that 
the ‘‘amphitene’’ or synaptic stage represents a 
progressive union of leptotene threads, two by two 
and side by side (parasynapsis), to form pachy- 
tene loops of the haploid number; and in the case 
of Batracoseps there is considerable evidence that 
this process is accompanied by a close torsion or 
twisting together of the leptotene threads as they 
unite. This process proceeds from one pole of the 
nucleus towards the opposite pole. In the opinion 
of the author it is impossible to admit the inter- 
pretation of this process offered by Fick, Gold- 
schmidt, Hecker and Meves that it is only a modi- 
fied form of longitudinal splitting. Observations 
on the Orthoptera (grasshoppers) indicate that a 
similar mode of synapsis occurs in these animals, 
though it is less certainly shown than in the 
other forms. In the pachytene loops resulting 
from synapsis all traces of duality are usually lost 
to view, at least for a time. This may be due 
either to a close twisting together of the leptotene 
threads or to an actual process of fusion. In 
either case there is as yet no satisfactory evidence 
that the plane of the ensuing ‘‘reduction-division’? 
is identical with that of the original conjugation. 
The facts point on the whole to the conclusion that 
the period following synapsis is one of reorganiza- 
tion of the chromosomes in which a redistribution 
of their substance may take place. This may be 
effected by a process of torsion as the chromo- 
