126 FISHERIES OF THE UNITED STATES. [20] 



years has remained at about the same standing. The demand for the 

 better grades greatly exceeds the supply. Fully 75 per cent, in value of 

 all the Florida Sponges marketed are of the Sheepswool variety. 



Sponge culture has recently attracted the attention of those interested 

 in the Florida Sponge fishery, since some of the older grounds have 

 shown signs of becoming exhausted. The recent successful attempts 

 at raising Sponges from clippings in the Mediterranean have inspired 

 hopes that similar practices might succeed well here, and the first trials 

 have been quite encouraging. In the present exhibit are included four 

 specimens of Sheepswool Sponges, grown from small cuttings at Key 

 West, but not, however, under the most favorable conditions. They 

 are numbered as follows: 771, 772, 773, 774. They were all planted 

 December 8, 1881, in a depth of 2£ feet of water, and represent six 

 months' growth, from an original height of 2£ inches. The smallest 

 specimen was planted in a small cove or bight, where there was little or 

 no tidal current, and hence its slight increase in size. The other three 

 specimens were placed in a tide-way, two being attached by wires and 

 the third by means of a stick running through it. The agent of Messrs. 

 McKesson & Bobbins, who made these experiments, states that it re- 

 quires at least four months for the Sponge to recover from the injury 

 done it in the cutting, which removes the outer skin along the edges of 

 the section. At the end of the first four months no apparent increase 

 in size had taken place, so that the growth exhibited is for two months 

 only. Two hundred and sixteen specimens in all were planted by the 

 same party at the above date, and at last accounts they were doing 

 nicely. The greatest difficulty in the way of Sponge culture about Key 

 West, at present, arises from the fact that the spongers are permitted to 

 fish everywhere without restriction, and it is impossible to select a 

 suitable spot without fear of its being molested. The agent claims that 

 with a grant, protecting a good tidal area of suitable depth and dimen- 

 sions, he can make Sponge culture a complete success. 



Boring- Sponge. — The Boring Sponge (Cliona sulphured) has the 

 power of excavating in limy structures, such as the shells of mollusks, 

 submerged marble, &c. It begins its life as a burrower, as frequently 

 into living as dead shells, and is at times a source of considerable irri- 

 tation to oysters and other shell fish, but probably does not cause much 

 destruction. In 1878, a cargo of Italian marble, which had been wrecked 

 in 1871 off Long Island, was taken up, and the blocks of stone were 

 seen to be thoroughly penetrated, to a depth of one or two inches, by 

 the crooked and irregular borings of this Sponge. Beyond the borings 

 the marble was still in good condition. 



