182 THE VOYAGE OF H.M.S. CHALLENGER. 



On the systematic position of Ilyalonema, Gray in 1859^ asserted that within the 

 group of polypes with feathered tentacles or Alcyonaria, and close to the " SabulicolaB " 

 which are rooted in the sand, and to the " Rupicolse " or Gorgonidse attached to 

 the rock, a third division might be formed, which on account of its rooting on sponges 

 might be named " Spongicolse," with the single genus Hyalonema. 



The opinion of Gray as to the polype nature of the remarkable glassy and filamentous 

 tuft, and which became fixed to a sponge, was shared by Brandt,'^ who in 1859 also 

 described the glassy spicular bundle as the axial skeleton of the cortical layer of the 

 polype. Brandt thought that two difierent genera of polypes could be distinguished, 

 viz., Hyalonema with plain discoid polypes, and Hyalochiete with cylindrical terminally 

 funnel-shaped solitary polypes, both of which he united in the single family 

 Hyalochastides. In the genus Hyalonema he described two species, namely, Hyalonema 

 sieboldii. Gray, and Hyalonema affine, Brandt ; of the genus Hyalochaeta only the single 

 species, Hyaloch^ta possieti. 



The loose fleecy mass in which the conical extremity of the glassy filamentous tuft is 

 usually embedded was referred to by Brandt as a " parasitic sponge " which had destroyed 

 the soft parts of the polype stock at its point of attachment, he also distinguished, 

 though he did not accurately describe, two species of this sponge as " Spongia spinicrux " 

 and " Spongia octancyra." The attachment of a group of Hyalonema to a Pholas- 

 bored stone by means of their conical projecting tufted extremity, which occurred in the 

 case of a specimen from Japan, Brandt regarded as artificial. 



Of this work by Brandt a critical review by Gray^ appeared in 1860. Gray asserted 

 that the two genera distinguished by Brandt with their three species were varieties of 

 one and the same species. Ehrenberg* also expressed an opinion during the same year 

 as to the nature of this remarkable organism ; he regarded the whole as a Japanese 

 artifice, compounded of long sponge spicules and a polype. 



A thorough investigation of several dried Hyalonemata from Japan was first under- 

 taken by Max Schultze. As a result of this he briefly expressed his views in regard to 

 the relation of the polype and sponge," to the efl"ect that the siliceous filiform cords and 

 the sponge body form an inseparable whole, and that accordingly the Hyalonema are to 

 be regarded not as polypes but as sponges. In the same year he published the results of 

 his accurate analysis of the formation and structure of the sponge, as well as of the 

 adherent polype crust, in a special monograph, illustrated by beautiful plates, entitled 

 Die Hyalonemen. The opinion expressed in the preliminary communication, that the 

 crust surrounding the spicular tuft also belonged to the sponge body, he soon retracted. 

 He believed that the large cylindrical sponge body became attached by means 



1 Avn. and May. Nat. Hist., ser. 3, vol. iv. p. 439. ' Symbolai ad polypos hyalochaetides spectantes. 



3 .47171. and Mag. Nat. Hist., ser. 3, vol. v. p. 229. * Monatsber. d. k. prevss. Akad. d. IViss. Berlin, p. 173. 



5 Comptes rendus, April 23, 1860, vol. 1. p. 792. 



