96 
Journal of the Mitchell Society [ November 
ologically embryonic, into a perfect sponge at any time of the 
year irrespective of the breeding season. We may even exer- 
cise some direct control over the size of the plasmodial 
masses, as the following experiment shows. 
Microciona was kept in aquaria until the degenerative pro- 
cess had begun. Pieces were then teased with needles in a 
watch glass of sea water in such a way as to liberate quanti- 
ties of cells and small irregular cell-agglomerates. These 
were gently forced with pipette to the center of the watch 
glass. Fusion of cells and masses, with amoeboid phenom- 
ena, began at once, and in half an hour quite large irregular 
masses existed. In the course of a few hours the masses 
grew enormously through continued fusion. From this time 
on they adhered firmly to the glass, retaining irregular plas- 
modium-like shapes, and the growth was inconspicuous. To 
bring them together once more and induce further fusion 
they were on the following day forcibly freed, with pipette 
and needle, and to clean them of cellular debris and bacteria 
were transferred to a tumbler (covering with bolting cloth) 
in which they were kept actively moving under a fine glass 
faucet for about thirty minutes. In the course of this violent 
agitation a good many masses were lost. Those remaining 
in the tumbler became in the next few hours noticeably 
rounder and smoother at the surface. From this experiment 
eighteen more or less spheroidal masses were obtained, some 
of which measured one half millimeter in diameter. They 
were similar to the small plasmodial masses produced in this 
species (and in Stolotella ) when the sponges are allowed to 
remain quietly in aquaria. As already stated, it is only in 
Stylotella that I have directly proved the regenerative power 
of these masses. 
Maas has just announced 3 that calcareous sponges ( Sycons ) 
when exposed to sea water deprived of its calcium undergo 
3 ‘Ueber die Einwirkung karbonatfreier und kalkfreier SaLzlosungen auf 
erwachsene Kalkschwamme und auf Entwicklungsstadien derselben. Ar- 
chiv fur Entwicklungsmechanik der Organismen,’ Bd. XXII., Heft 4, 
December, 1906. 
