Prof. Ehrenberg on Hyalonema lusitanicum. 419 



LXII. — On Hyalonema lusitanicunij and on the Animal or Ve- 

 getable Nature of Sponges. By Protcssor Ehuexberg'^'. 



That the glass-plant {Hyalonema Bieboldii), which had been 

 previously regarded as a polype with a siliceous axis^ is only an 

 artificial product of Japanese industry, the sihceous axis of 

 which has been brought into an unnatural union with foreign 

 substances, including polypes and sponges, by means of thread 

 and wire, was stated by me in 1860 and 1861, as is published in 

 the ' Monatsberichten ' of those years. The true origin of sili- 

 ceous axes resembling threads of glass as evidently concentric or- 

 ganic structures was then inexplicable. 



In the year 1864 Professor Barboza du Bocage, of Lisbon, 

 described, in the * Proceedings of the Zoological Society of 

 London,^ a new species of the interesting glass-plants from 

 the European seas off Portugal ; but its habitat was not then 

 quite certain. As the point whether these are polypes with 

 a siliceous axis appears to me to be of essential significance for 

 the physiological conception of systematic zoology, I regard 

 this subject as not unworthy of being mentioned again to the 

 Academy. The locality of the so-called Hyalonema lusitanicum, 

 which was founded upon a single specimen, was still doubtful 

 in 1864; but, according to a more recent notice by the same 

 naturahst in the same journal (Proc. Zool. Soc. 1865, p. 662), 

 it has been established with certainty by the discovery of new 

 examples. Besides the first specimen, the Museum at Lisbon 

 now possesses two others, likewise obtained from Setubal, and 

 also numerous isolated siliceous filaments, which appear to be- 

 long to three or four different individuals. The two perfect 

 specimens are 17 and 29 inches in length, and the largest is 

 very beautifully preserved. The discoverer says that in the 

 best-preserved, largest, and most perfect specimen a skin 

 (corium) completely envelopes the axis. He now thinks that 

 this form is established not only systematically, but also as be- 

 longing to the Portuguese seas, and that it is not even rare. The 

 superstitious fishermen know it very well ; they call it Cravache 

 de la Mer (Sea-whip), and when it makes its appearance they 

 fear bad success in their fishing. It is found in the apparatus 

 used in the Dogfish fishery, and is immediately torn to pieces 

 and thrown into the sea by the fishermen. 



As regards the nature of this body, Professor Barboza du 

 Bocage docs not share the opinion of those naturalists who re- 

 gard the Japanese form as the production of a sponge, but takes 

 part with those who consider it a polype. On no specimen of 



* Translated from the ^ Monatsbcricht tier Berliner Akad. der Wissen- 

 schaften/ Deeember 1866, pp. 823-837, by W. S. Dallas, F.L.S. «fc. 



