266 Dr. J. E. Gray on Hyalonema Sieboldii. 



ends of the separate spicule, and, from tlie same character, 

 equally if not more easy to determine the ends of the coil of 

 spicules. The spicules of Hyalonema are elongate, unequally 

 fusiform : that is to say, thicker in tlie middle portion and ta- 

 pering at each end ; but the lower tapering part of the spicules 

 is much the longest, and it tapers to a much more slender and 

 finer point — the end above the thickest part tapering very 

 gradually and being truncated before it reaches to a slender 

 point. The consequence is that the coil is always much thicker 

 in the upper part, from the greater thickness of the spicules, 

 than in the lower one. 



Since I have seen these specimens, I have a strong belief that 

 the Hyalonema Sieboldii ^ fig. 1. pi. 1 of Brandt's ' Symbola?,' 

 and most probably of Hyalochceta Possieti^ t. 2. f. 6, are free 

 corals, with the basal end covered with bark ; but he did not 

 so regard them. I may also observe that the spicules figured 

 (t. 2. f. 12 & 13) are represented on the plate with what he 

 calls the upper part or free end of the spicule towards the 

 bottom of the plate. 



The specimens of this variety are exactly like the free spe- 

 cimens that M. Bocage found on the Portuguese coast ; and 

 they show that both the Japanese and the Portuguese species 

 are sometimes found free, without any sponge at the base, and 

 at others growing from a mass of sponge ; and it has been 

 lately observed that sometimes even two corals will grow 

 from the same sponge. 



I think this goes far to show that the attachment of the 

 coral to the sponge is not a necessity, but only a frequent 

 habit, and to prove that the coil of spicules is not a develop- 

 ment of the spicules of the sponge to which it is attached. If 

 this were the case, the sponge, which would be so important 

 to its development, would always be present ; for if the coil is 

 the development of the spicules of the sponge in which it lives, 

 how are the spicules developed when there is no sponge at 

 the base to develop them ? 



The coil itself cannot be a sponge, as it is destitute of sar- 

 code, inhalant pores, and excurrent oscules — the distinctive 

 characters of sponges. 



On the other hand, if we regard the spicules as the secretion 

 of the animal that invests them, all these difficulties disappear; 

 and every part of the structure leads to this conclusion. 



This series of specimens is very instructive ; and I have 

 been able to secure a part of them for the British-Museum 

 Collection, so that they may be examined by any one interested 

 in the controversy. 



First, all the specimens, like all the others received from 



