Dr. J. E. Gray on the " Glass-Rope" Hyalonema. 295 



ing them as parts of the same animal " (Ann. & Mag. Nat. Hist. 

 1859, iv. 441). And the discovery of a second species in Japan, 

 and a third on the coast of Portugal, in all of which the bark 

 and axis are found together, I think entirely destroys any idea 

 that there is the slightest reason for believing the theory 

 propounded by Valenciennes, and which has been so readily 

 adopted, I may almost say without re-examination, by other 

 naturalists. 



This theory has had the effect of confusing the nomenclature 

 of the Japanese species, which I first described as under : — 



I. The coral consisting of the bark and axis. 



Hyalonema Sieboldii, Gray, P. Z. S. ii. 1835, p. 63 ; Brandt, Sym- 

 bols, &c. t. 1. f. 1, 10. 

 Halinema, Ehrenb. Monatsb. Berlin, 1840, p. 3 & 3 (a misprint ?). 



II. The bark only, without the axis or sponge. 

 Polythoa fatua, Max Schultze, Hyalonemse. 



III. The sponge without the rope-like axis or bark. 

 Spongia octancyrce, Brandt, Symbolae, 14, note; Ehrenberg, 



Monatsb. 1860, p. 170. 

 Spongia crucigera, Ehrenb. Monatsber. 



IV. The sponge and the elongated united axis without the bark and animal. 

 Hyalonema Sieboldii, Max Schultze, Die Hyalonemen, 9. 

 Hyalonema mirabilis, Gray, Bowerbank, Brit. Spongiadse, 49. 

 Hyalonema, Valenciennes, Milne-Edwards and Haime. 



This coral, which was first regarded as a plant and then as a 

 sponge, has been considered by one of the first microscopists 

 an artificial production ! Thus Professor Ehrenberg, in an 

 elaborate paper in which he gives an abstract of the various 

 essays that have been written on the Hyalonema Sieboldii, con- 

 cludes thus : — 



" Glass- corals must be considered an artificial production, not 

 less than those Indian idols produced in the shells of mother-of- 

 pearl. The long siliceous threads, widely distribut;pd over the 

 Pacific, are with much labour collected in small quantities, pro- 

 bably from an unknown large species of Tethyay they are 

 formed into bundles, which are forced into or through the tubular 

 leather-corals allied to Polythoa, so that the fine end of the 

 bundle, which is first pushed through, remains simple, whilst 

 the remainder obtains a .spiral form through the rotatory maui- 



