266 Dr. J. E. Gray on Hyalonema Sieboldii. 
ends of the separate spicule, and, from the 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 the 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 tapermg 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. pl. 1 of Brandt’s ‘ Symbole,’ 
and most probably of Hyalochwta 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 & 18) 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 
