240 Thirty-Third Annual Meeting 
that certain cuttings grow but little or not at all even though 
they live for several years. Why this is so has not been deter- 
mined but it is probable that some parts of some sponges have 
reached a stage where they are incapable of further extensive 
growth and when a cutting is taken from such parts it under- 
goes no increase in size. Whether there is a limit to the size to 
which a sponge will grow under natural conditions, and if there 
is a limit what imposes it is not known. If it should be the 
result of the disparity, growing with the diameter, between the 
surface area and the volume, then the inhibition would not apply 
to the cuttings until they had reached at least the approximate 
size of the parents. If on the other hand there be some inherent 
or inherited limit, say to the number of cell generations from the 
egg, then the excision of pieces from the sponge would not 
change this and the cuttings would not grow in the aggregate 
to a weight beyond that of the original sponge had it remained 
intact and unmolested. If this latter suggestion should prove 
correct, it would be a serious though not fatal objection to the 
method of raising sponges from cuttings. In the results so far 
obtained there is no reason to anticipate failure or partial failure 
from the cause, though during the present summer the mortality 
among the larger sponges has been somewhat alarming. 
On the whole, the progress of the experiments and their 
future are promising. Growth while showing some irregulari- 
ties in rate has been fairly rapid. Cuttings originally measuring 
about two inches by one inch have in eighteen months developed 
into spheroids four inches in diameter. These are larger and 
heavier than many of the natural sponges put on the markets, 
but the price brought by sponges of this size is so low that it 
would not be profitable to raise them. The largest sponges which 
have been grown were from cuttings of the size mentioned above 
and in thirty months measured nearly six inches in their longest 
diameter. This, however, was above the average. 
Concerning the proportion of survivals, an important con- 
sideration, nothing very definite can be said. The exigencies of 
experimental work have made it necessary to frequently change 
the conditions under which the sponges were growing, the origi- 
nal wires and other supports were replaced in some cases two or 
three times, mishaps occurring during the absence of the ex- 
