1867.] DR. J. E. GRAY ON HYALONICMA LUSITANICUM. 119 



The want of more materials makes it impossible to eome to any con- 

 clusion as to the distinctness of the genera or even of the species. 



If one may judge from the figure of Professor Brandt, the polypes 

 of the genus Hyahchceta appear to be on the slender end of the axis 

 of the coil of the coral, as in the Portuguese species. It would be 

 desirable to know whether this form is ever I'ound living in a s[)onge. 



The specimen in the British Museum, obtained by Dr. W. Lock- 

 hart in Japan, which has some of the polypes prominent and clus- 

 tered, has the bark only on the lower, more slender end of the coil, 

 and in this respect agrees to some extent with Professor Brandt's 

 figure. But the slender end of the coil projects like a pencil beyond 

 the bark ; and one is by no means sure that the bark, whicli is evi- 

 dently very easily moved on the axis in the living or freshly gathered 

 coral, may not have been slipped down towards that end of the coil ; 

 and I think that this may be the case, as I believe that it was ob- 

 tained with the other Japanese specimens of H. sieboldii which Dr. 

 Lockhart brought home. In this respect it differs from the Portu- 

 guese species and from the Hyalochccta of Prof. Brandt ; for in both 

 of them the bark entirely covers the base of the axis, and evidently 

 belongs to that part of the specimen. 



2. Hyalothrix. 



The polypes with forty tentacles in several concentric series, the 

 outer series the largest. The axis, covered to the very base with the 

 polype, bearing bark, and the bark strengthened with cylindrical 

 filiform siliceous spicules, and with a smooth external coat without 

 any imbedded granules. 



This genus is at once distinguished from Hyalonema by the coral 

 not living with its base immersed in a sponge. It Uves evidently 

 free ; but how it keeps itself in an erect position so that all the po- 

 lypes round the axis may obtain food is yet to be discovered. 



I. Hyalothrix lusitanica. 



Hyalonema lusitanicum, Bocage, P. Z. S. 1864, p. 26r>, pl.xxii.; 

 1865, p. 662 ; Gray, Ann. & Mag. N. H. 1866, xviii. p. 287. 

 Hub. Coast of Portugal (ZJoea^e). B.M. 



After the study of all the specimens which I have been able to 

 see from Japan, and of the Portuguese specimen, I still adhere to 

 the opinion that I formed when I first described the genus, now 

 more than thirty years ago, and which is so well supported by Prof. 

 Brandt in his carefully prepared and well-studied memoir. I re- 

 gard Hyalonema as a type of a peculiar family of ('orals, formed bv 

 zoanthoid polypes, characterized by forming for their support a sili- 

 ceous axis formed of many thread-like spicules coiled together into 

 a rope-like form, each formed of numerous concentric laminae, and 

 surrounded and separated from one another by the corium of the 

 community of polyj)es. 



I am aware that M. Valenciennes has suggested that the rope-like 

 coil or axis in the Japanese species is a part of the sponge, and regards 



