l8 BULLETIN OF THE BUREAU OF FISHERIES. 



Experiment record 2, August j, igo6. — Question involved: Can masses of regenera- 

 tive tissue such as were produced in experiment i , be made to unite and to form outside 

 the sponge body smooth gemmule-like masses such as are produced in sponges allowed 

 to degenerate slowly in aquaria ? Yes. 



A branched Microciona in which degeneration had begun was selected. The 

 regenerative tissue forms a core in the lobes and discrete masses here and there. Pieces 

 of the sponge were teased in sea water and the regenerative tissue broken up as before. 

 The cells and cell agglomerates were gently forced with pipette to center of watch glass. 

 Fusion of cells and masses, with amceboid phenomena, 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 plasmodium-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 (covered with bolting cloth) in which they were 

 kept actively moving under a fine glass faucet for about 30 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 18 more or less spheroidal masses were obtained, some of which measured 

 }4 rnm. indiameter. They were similar to the small plasmodial masses produced in 

 this species when the sponges are allowed to degenerate slowly in aquaria. 



Experiment record j, July ij, 1907. — Question involved: When regenerative tissue 

 is removed from a degenerating sponge and induced to form masses of some size, will 

 these masses transform into perfect sponges? Result was negative. 



A branched Microciona that had been kept in aquarium some days was used. 

 Degeneration had set in and regenerative tissue formed as above. Lobes were teased 

 in watch glasses of sea water. The cells and minute cell masses settle down on the 

 bottom like a fine sediment, resembling in appearance small invertebrate eggs. Some 

 fusion quickly takes place. The material is then brought together in the center of the 

 watch glass, where it forms a loose aggregation about 10 mm. in diameter and i mm. or 

 less thick. This is left for half an hour for further fusion to take place and is then 

 immersed in a crystallization dish of sea water. The mass of sponge tissue adheres to 

 the bottom of the watch glass. Two such watch glasses (Minot glass) were prepared. 

 About an hour later, to induce further fusion and concentration, the tissue was freed 

 from the bottom of the glass, and the various masses brought together in as dense a 

 heap as possible. 



About two hours later the condition of the aggregate was as follows. The appear- 

 ance is essentially like that of the rough excrescences of regenerative tissue which occur 

 on the surface of Microciotia when the latter degenerates in aquaria. Much of it is 

 simply an amorphous mass of dense, syncytial, sponge tissue. But this tissue has 

 a tendency to round off into compact smooth nodules or lobes or free rounded masses. 



