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 
papille being regularly disposed and of a nearly uniform size; 
and there are generally two, and sometimes three, papille or 
animals quite at the end, which is more or less 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 different 
* Tam aware that Dr. Bowerbank states that M. Bocage has mistaken 
the ae 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 papille, and the 
animal of the Portuguese and Japan specimens are alike, or his declara- 
tion that the papillz 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 Hyalonema [meaning 
the sponge to which the coil is attached] has sponge-structure,” which 
T never denied (P. Z. 8. 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. 8.1867, 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. 
