SPONG1DA. 73 



same time, however, the trade in this product goes on yearly increasing. 

 But it is only a question of time when the trade shall cease ; the 

 demand which every year clears the submarine fields of these sponges 

 causing such destruction that their reproduction will soon cease to be 

 adequate. 



In order to prevent such a result, it is very desirable that 

 attempts should at once be made to naturalise the several species of 

 sponges on the French and Algerian coasts, and that their cultivation 

 and reproduction should be protected. For this purpose the rocky 

 coasts of the Mediterranean, from Cape Cruz to Nice, at Hyeres, 

 and even some of the salt lakes of the departments in Algeria near 

 the Mediterranean, might be utilised ; large portions of the Southern 

 Italian littoral zone would also be available for this purpose. 



M. Lamiral considered that the composition of the water of the 

 Mediterranean being nearly the same on the coasts of France, of 

 Algeria, and of Syria, the difference of temperature between these 

 two places especially at the depth where the sponges flourish most 

 would not interfere with their existence, and he believed that 

 their acclimatisation on the coasts of France and Algeria wou!4 be a 

 certain success. He remarked, moreover, that the more the sponges 

 advanced towards the north the finer and compacter their tissues 

 became ; and he argued from this fact that a considerable improve- 

 ment in their quality would result from the experiment. 



The only difficulty, then, would be in the transplanting sponges 

 from the Syrian waters to the coasts of France and Algeria. A sub- 

 marine boat, such as M. Lamiral makes use of for scientific operations 

 conducted in deep water, would, according to this naturalist, give 

 every facility for collecting sponges for the purpose. This 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, which is 

 conveyed by an air-pump and tube into the interior of the boat from 

 above, so that the men could readily select such specimens as were 

 suited for acclimatising ; removing whole blocks of rock along with 

 them, either by placing them in cases pierced with holes, or by 

 towing them to their new abode. 



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 transplant them to favourable 

 localities. At the end of three years, when these true submarine 

 fields would be probably ripe for harvesting, they could be farmed 

 out for methodical collection, which would be effected by means of 

 diving boats. 



