PRESERVATION OF SPONGE FISHERIES. 127 



In order to prevent this result, it has been suggested 

 that attempts should be made to naturalize the several 

 species of sponges, and that their cultivation and reproduc- 

 tion should be protected. The first thing to consider is 

 what waters have the same or nearly the same temperature 

 as that in which the sponges now dwell. This being com- 

 paratively easy, the next and most difficult part would be to 

 transfer the animals in such a shape as would insure repro- 

 duction in their new homes. Some such submarine boat as 

 has been used recently in making scientific operations con- 

 ducted in deep water, might, probably, give the necessary 

 facility for collecting sponges for the purpose. Such a boat 

 can descend to great depths, and its crew can even dwell 

 there for a considerable time, for it is continually fed with 

 fresh air ; so that the men could readily select such specimens 

 as were suited for acclimatizing, removing whole blocks of 

 rock along with them. 



It might be possible too to collect the very young forms 

 of sponge in the months of April and May, shortly after they 

 have commenced their independent existence, and to trans- 

 plant them to favorable localities. At the end of a few 

 years, when these true submarine fields would be probably 

 ripe for harvesting, they could he farmed out for methodical 

 collection, which would be effected by means of diving 

 boats. 



