124 SPONGES. 



of the depots for the sponges of commerce. The 

 species which live immediately along the shore 

 near the water's edge, though often large, are 

 worthless. These are of many colours ; some of 

 the brightest scarlet or clear yellow, form a crust 

 over the faces of sub -marine rocks ; others 

 are large and tubular, resembling Holothurice in 

 form, and are of a gamboge colour, which soon 

 turns to dirty brown when they are taken out 

 of the water; others, again, are lobed or palmate, 

 studded with prickly points, and perforated at 

 intervals by osculi. These grow to a considera- 

 ble size, but, like the former, are useless, since 

 their substance is very full of silicious spicule. 

 Many species, indeed, are made up of interlacing 

 bundles of spicule, with animal matter in the 

 intestines. The larger kinds are not found deeper 

 than thirty fathoms, and most of them within 

 a third of that depth. A few small species live 

 at very great depths, and one was taken alive 

 in the Gulf of Macri in one hundred and eighty- 

 five fathoms water. 



The sponge of commerce is found attached 

 to rocks in various depths between three fathoms 

 and thirty. When alive it is of a dull bluish 

 black above, and of a dirty white beneath. There 



