THE INTELLECTUAL OBSERVER. 



MARCH, 186 7 



ON THE " GLASS-ROPE " HYALONEMA. 



BY PKOFESSOR WYYILLE THOMSON. 



(With a Coloured Plate.) 



A bundle of from 2- to 300 threads of transparent silica, glisten- 

 ing with a satiny lustre, like the most brilliant spun glass ; 

 each thread about 18 inches long ; in the middle the thickness 

 of a knitting needle, and gradually tapering towards 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 

 lower portions remaining compactly coiled by a permanent 

 twist of the individual threads ; the upper portions of the coil 

 frayed out, so that the glassy threads stand separate from 

 one another, like the bristles of a glittering brush ; the lower 

 extremity of the coil imbedded perpendicularly in the middle of 

 a hemispherical or conical undoubted sponge, and usually 

 part of the exposed portion of the silicious coil and part of 

 the sponge covered with a brown leathery coating, whose surface 

 is studded with the polyps of an equally undoubted zoantharian 

 zoophyte. Such is the general effect of a complete specimen of 

 Hyalonema Sieboldi (Gray), a marvellous organism first brought 

 to Europe from Japan, by the celebrated naturalist and tra- 

 veller Von Siebold j and now to be found, more or less perfect, 

 in most of the European Museums. 



When the first specimen of Hyalonema was brought home, it 

 stood in this peculiar position, that nothing had been seen in the 

 least like it before, and the history of opinion as to its relations 

 is curious. The being consisted of three very distinct parts : — 

 first, and infinitely most remarkable, the twist of silicious need- 

 les ; then the sponge, whose lower surface had evidently been 

 attached to some foreign body, and which served as a sort of 

 pedestal, from the top of which the flinty brush projected, 

 spreading out above it in the water ; and, thirdly, the ap- 

 parently constant zoophyte. This complicated association 

 suggested a multitude of possibilities. Was Hyalonema a natural 

 vol. xi.— no. ir. a 



