DEEP SEA FAUNA 1311 



Hyalonema, with the coils in the larger examples up- 

 ward of 40 centimetres in length. 



A bundle of from 200 to 300 threads of trans- 

 parent silica, glistening with a silky lustre, like the 

 most brilliant spun-glass each thread from 30 to 40 

 centimetres long, in the middle the thickness of a 

 knitting-needle, and gradually tapering toward 

 either end to a fine point; the whole bundle coiled 

 like a strand of rope into a lengthened spiral, the 

 threads of the middle and upper portions remaining 

 compactly coiled by a permanent twist of the indi- 

 vidual threads; the lower part of the coil, which, 

 when the sponge is living, is imbedded in the mud, 

 frayed out so that the glassy threads stand separate 

 from one another, like the bristles of a glittering 

 brush; the upper portion of the coil close and com- 

 pact, imbedded perpendicularly in a conical or 

 cylindrical sponge; and usually part of the upper 

 portion of the silicious coil, and part of the sponge- 

 substance, covered with a brownish leathery coating, 

 whose surface is studded with the polypes of an al- 

 cyonarian zoophyte such is the general effect of a 

 complete specimen of Hyalonema. 



The genus was first known in Europe by specimens 

 brought from Japan by the celebrated naturalist and 

 traveler, Von Siebold; and Japanese examples of 

 Hyalonema sieboldi, Gray, may now be found more 

 or less perfect in most of the European museums. 

 When the first specimen of Hyalonema was brought 

 home, the other vitreous sponges which approach it 

 so closely in all essential points of structure were 

 unknown. 



