Dr. J. E. Gray on Hyalonema Sieboldii. 265 



The attached variety is generally of a larger size and greater 

 diameter ; but they are known, even when the sponge is ab- 

 sent, by the basal portion sunk in the sponge being conical 

 and tapering to a fine point formed of the very slender ends 

 of the spicules. Six specimens of this variety have the 

 sponge attached to the coils. The sponges vary considerably 

 in, size ; but they are all more or less oblong, and most of them 

 show more or less distinctly, according to the care that has 

 been taken of them when they were collected and packed, the 

 circular oscule, with its prominent edge, that is well repre- 

 sented in Professor Schultze's plate in his essay on the coral. 

 The three other specimens have the naked conical base of the 

 coil, and have, no doubt, been separated from the sponge 

 when they were collected. 



The six specimens of the free variety are all rather smaller 

 and more slender than the majority of the other specimens ; 

 they have the lower half of the coil covered with bark to the 

 base. The coil in these specimens does not suddenly taper to 

 a fine point, as in the specimens that are taken out of sponges, 

 but is only a very little smaller in the diameter of the base 

 than in the middle length of the specimen. The bark of 

 these specimens has never been removed, the tubercles or 

 papillas being regularly disposed and of a nearly uniform size; 

 and there are generally two, and sometimes three, papillae or 

 animals quite at the end, which is more or Idss truncated, and 

 in the dried specimens sometimes bent up or recurved. 



There can be no mistake as to the end of the coil that is 

 covered with the bark*; for it is easy to determine the difierent 



* I am aware that Dr. Bowerbank states that M. Bocage has mistaken 

 the upper part of the Portuguese specimen for the lower ; but this is only 

 a proof of the very cursory and incomplete manner in which he examined 

 the Portuguese specimens in the British Museum ; for any one who is 

 acquainted with the structure and organization of the spicules of Hyalo- 

 nema cannot possibly mistake one end of them for the other. The state- 

 ment is as inaccurate as his assertion that the bark, the papillae, and the 

 animal of the Portuguese and Japan specimens are alike, or his declara- 

 tion that the papillae or contracted animals are oscules, and have no ten- 

 tacles nor cnidia, in defiance of the observations of Brandt, Schultze, 

 and Bocage, as well as myself. It is rather a difficult matter attempting 

 to discuss a scientific question with Dr. Bowerbank. For example, when 

 I say ^''Hyalonema [meaning the coil] has no sponge-structure," he re- 

 plies, "Brandt, Schultze, &c., have proved that Hyalmiema [meaning 

 the sponge to which the coil is attached] has sponge-structure," which 

 I never denied (P. Z. S. 1867, p. 905). When I said, " silica is not 

 exclusively secreted by sponges, as the advocates of the sponge theory 

 seem to believe," he replied, "no one ever asserted that silica is ex- 

 clusively secreted by sponges ;" yet a little lower down in the same page 

 (P. Z. S. 1867, p. 904) he argues that the spicules of Hyalonema must have 

 been secreted by sponges, as silica is only secreted by the Protozoa — that 

 is, sponges. 



