180/.] DR. J. E. (JKAY ON II YAI.ON KM A LUSITAMCUM. ]'23 



the small end of the coral, ivhich in the Japan species is sunk in the 

 sponge, covered with polypes like the rest of its surface. 



Professor Max Schiiltze, who regards the coil of the Japanese spe- 

 cies as part of the sponge and the polypes as a parasitic species of 

 Palythoa, considers the polype an undescribed species of that genus. 

 But the observation of Professor Brandt shows that it differs from 

 all the species of the genus Palythoa in having the inner layer of 

 the basal portion, which forms the bark of the coil and the cells 

 of the polypes, strengthened with siliceous spicula, similar to, but 

 smaller and shorter than the spicula of the coil ; so that the animal 

 must form a genus by itself, which has the peculiarity of secreting 

 small spicules of the same kind and form as those which the advo- 

 cates of the parasitic theory will not admit the polype secretes of 

 a larger size so as to form the coil. 



According to the observations of Professor Bocage, the polype of 

 the Portuguese species differs from that of the Japan species in having 

 a different number of tentacles ; but it agrees with the Japan species 

 in the inner layer of the corium secreting siliceous spicules. So the 

 Hyalonemata of the two localities have polypes agreeing in forming 

 siliceous spicules in the corium, and yet may be referred to different 

 genera. Yet we are to believe that each is only parasitic on a coil 

 of spicules which only diifers from the spicules of their flesh in 

 being larger and formed into a central coil ! This I must regard as 

 a very illogical conclusion, as it is more natural to suppose they se- 

 crete the spicules of the bark and the coil. 



These two genera, according to the theory entertained by Valen- 

 ciennes, Milne-Edwards, and Wyville Thompson, must belong to 

 two very different groups of animals. These zoologists consider the 

 " glass rope," because it grows out of a sponge* having somewhat 

 similar siliceous spicula, to be only an extraordinary development of 

 the spicula of the sponge, which is covered with a parasitic Palythoa ! 

 Therefore they regard it as a sponge. As the second genus does 

 not grow out of a sponge, and therefore cannot be a development of 

 the sponge-spicula, and therefore cannot be a sponge, I do not know 

 to what group of animals they would refer it. I therefore think it 

 much more reasonable to believe that both belong to a peculiar 

 group of zoanthoid corals characterized by secreting an axis formed 

 of siliceous thread-like spicules, consisting at present of two genera, 

 one living free, and the other growing from a mass of sponge. 



Thus a coral with an axis formed of a coil of siliceous spicules, 

 exactly similar to that of Hyalonema, is found without being in con- 

 nexion with any sponge ; so that the coil cannot be a special deve- 

 loj)ment of the spicules of a certain sponge. In the latter case the 

 coil-like axis is evidently secreted by the polypes which cover it. 

 Are we to believe that the sponge forms the axis in one case, and 



* Professor Brandt denies that the Japan Hyalonema lives in a sponge {Hyalo- 

 nema, p. 14, note), and says he does not know how they are fixed (p. 14). Pro- 

 lessor Max Schultze figures three specimens in sponges (t. 1, 2). We have two 

 examples in the British Musemn in sponges; and I have seen more than a dozen 

 otlier specimens all growing in sponges. 



