422 THE DEPTHS OF THE SEA. [chap. vn. 



The genus was first known in Europe by specimens 

 brought from Japan by the celebrated naturalist and 

 traveller, Von Siebold; and Japanese examples of 

 Ilyalonema sieboldi, Gray, may now be found more 

 or less perfect in most of the European museums. 

 When the first specimen of Ilyalonema was brought 

 home, the other vitreous sponges which approach it 

 so closely in all essential points of structure were 

 unknown, and the history of opinion as to its rela- 

 tions is curious. 



The being consisted of three very distinct parts : 

 first, and greatly the most remarkable, the coil 

 of silicious needles ; then the sponge, and for long 

 it was supposed that this was the base of the struc- 

 ture, — from which the glossy brush projected, spread- 

 ing out above it in the water ; and thirdly, the 

 apparently constant encrusting zoophyte. 



This complicated association suggested many pos- 

 sibilities. Was Ilyalonema a natural production at 

 all ? Was it complete ? Were all the three parts 

 essentially connected together ? And if not, were all 

 the three independent, or did two of three parts 

 belong to the same thing ? and if so, which two ? 



Ilyalonema was first described and named in 

 1835 by Dr. John Edward Gray, who has since, 

 in one or two notices in the 'Annals of Natural 

 History ' and elsewhere, vigorously defended the 

 essential part of his original position. Dr. Gray 

 associated the silicious whisp with the zoophyte, 

 and regarded the sponge as a separate organism. 

 He looked upon the silicious coil as the representa- 

 tive of the horny axis of the sea-fans (Gorgonio?), 

 and the leather-like coat he regarded as its fleshy 



