I2J DR. J. E. GRAY ON HYALONEMA LUSITANICUM. [Jail. 24, 



1 consider that this structure of the corium is enough to prove 

 that it is the community of polypes that constitute the hark that 

 forms the coil of spicules, and that they are too intimately comiected 

 with the spicules to be only parasitic on their surface. 



IV. The essential character of a sponge is, that it is permeated 

 by canals for the circulation of the water which is emitted by 

 oscules ; and there is no such structure in Hyalonema. 



The sponge in which the Japanese Hyalonema is found is of the 

 normal structure here noted. But there is no appearance of any 

 canal in the coil of spicules ; indeed they are all formed into a close 

 mass, adherent together by the corium that surrounds each spicule. 



There is no communication between the canals of the sponge to 

 which the Hyalonema is attached and the axis of Hyalonema, which 

 has been regarded as part of the sponge. 



The s|)onge forms a condensed hard case, round the base of the 

 coil which is inserted in the sponge, very different from the rest of 

 the sponge, of a dense structure, and without any canal in it, as if 

 to separate the base of the Hyalonema from it as completely as 

 possible, evidently regarding the Hyalonema as an intruder, I sup- 

 pose, the base being enclosed in the hard case without any canal, 

 and the upper free part of the axis being entirely covered with 

 the polype-bearing corium or bark (or with the mass of parasitic 

 Palythoce, if that theory be the correct one) ; and I have seen speci- 

 mens which show that in the perfect state of the animal the axis is 

 so covered. 



This bark being destitute of pores or other apertures, and the axis 

 destitute of any canal, shows that the axis and bark cannot be any 

 oart of the " cloacal system," as Dr. Bowerbank states them to be in 

 liis characters of the genus, and, indeed, have no connexion with the 

 sponge in which it lives. 



In the perfectly formed specimen the coil of the axis reaches to 

 the base of the sponge, the coil gradually tapering in thickness until 

 it reaches the base, where it is like a small pencil of very thin spi- 

 cules. This thin end or pencil is closed over by the sponge. I be- 

 lieve that the coral commences on the surface of the sponge ; and 

 that as the coral increases in size the basal portion perforates and 

 descends in the sponge as the upper part of the axis ascends or 

 enlarges in size. 



In fact the coil of spicules forms no part of the organization, and 

 has no organic connexion with the sponge in which it is placed, 

 there being no water-current between it and the sponge, which is 

 the essential character of sponges. It is to be observed that neither 

 M. Valenciennes, Professor Max Schultze, nor Dr. Bowerbank at- 

 tempt to prove that the coil is in any way organically connected 

 with the sponge. 



V. The attachment to the sponge appears to he the habit of a single 

 species ; for the Portuguese species, which agrees with the Japanese 

 in most of its essential characters, lives free in the sea, and has 



