ON SOME PHENOMENA OF COALESCENCE AND 
REGENERATION IN SPONGES 1 
BY H. V. WILSON 
I 
III a recent communication I described some degenerative 
and regenerative phenomena in sponges and pointed out that 
a knowledge of these powers made it possible for us to grow 
sponges in a new way. The gist of the matter is that sili- 
cious sponges when kept in confinement under proper condi- 
tions degenerate in such a manner that while the bulk of the 
sponge dies, the cells in certain regions become aggregated 
to form lumps of undifferentiated tissue. Such lumps or plas- 
modial masses, which may be exceedingly abundant, are often 
of a rounded shape resembling gemmules, more especially the 
simpler gemmules of marine sponges (Chalina, e. g.), and 
were shown to possess in at least one form (Stylotella) full 
regenerative power. When isolated they grow and differen- 
tiate, producing perfect sponges. I described moreover a 
simple method by which plasmodial masses of the same 
appearance could be directly produced (in Microciona). The 
sponge was kept in aquarium until the degenerative process 
had begun. It was then teased with needles so as to liberate 
cells and cell agglomerates. These were brought together 
with the result that they fused and formed masses similar in 
appearance to those produced in this species when the sponge 
remains quietly in aquarium. At the time I was forced to 
lReprinted from Journal of Experimental' Zoology, vol. v, no. 2., and 
published with the permission of Hon. Geo. M. Bowers, U. S. Com- 
missioner of Fisheries. 
.7907] 
161 
