530 
David H. Dolley 
These central motor cells in the supra-oesophageal ganglion of tlie 
enibryo and new-born afford just as convenient an object of investiga- 
tion as in the adult. Even before birth they stand alone in their extent 
of development and serve as their own section mark of identification. 
Longitudinal sagittal sections of the embryos or of the heads of the larger 
young animals are the most suitable. The data of these measurements 
are set forth in Table VIII. The first group of three pairs of cells are 
froni embryos frorn the same mother, freed from their egg shell vhen 
apparcntly just about to hatch. The next group of six are young re- 
moved from two other animals which had been hatched from one to 
two days as nearly as could be determined. There is no need to separate 
them, for the differences in size within the same nest are as great as be- 
tween the two. The thlrd group consists of young ones which had left 
the mother and were freely swimming in the aquarium about a week 
after hatching. These varied in size, the largest being not over seven 
and one half millimetres. VTiile it does not affect the point in hand, 
unfortunately tlie conditions were unfavorable ; first as regards the animals 
tliemselves in that the tap water was too cold and hampered greatly 
their development; second several hatchings of different ages became 
mixed. Consequently though material up to three weeks was examined 
Chance has afforded no more advanced development than the maximum 
in the table and search appeared a waste of effort. 
So far as they go the results confirm the logical expectation that 
even the most hypertrophied ceUs Start on the same plane as others of 
theu’ type. In the embryonic group, the nucleus-plasma relation is 
comparatively more in favor of the nucleus. In the next group are 
to be noted the irregularities of transition to functional activity, whüe 
in the last group the uniform relation has been fairly weil attained. 
This relation, just as in the results from the adult cell, holds constant 
for an increase of total cell size to at least double the average size 
at birth. 
It will be noted that the figiures for the nucleus-plasma coefficients 
throughout tend to run slightly lower than for the adult cell. This would 
find satisfactory explanation in Popoff’s (1908) findings that the effect 
of cold is to disturb the balance in favor of the nucleus. Having no 
comparison with young animals under normal conditions, the associatcd 
absolute enlargement of both ceU and nucleus cannot be connected there- 
with. Several points are at once suggested by these and other measure- 
nients made which will be passed over to await more normally conserved 
and orderly material. 
