294 Dr. J. E. Gray on the “Glass-Rope” Hyalonema. 
“T/aspect granuleux, chagriné, que présente la surface exté- 
rieure du corium et des polypes n’est pas le résultat d’une simple 
incrustation de détritus de sable (comme on l’affirme pour les 
individus du Japon), mais il est di A la présence d’un nombre 
infini de spicules réguliers, en forme de massue et hérissés de 
pointes. Ces spicules font partie intégrante de la couche la 
plus extérieure ou tégumentaire. 
“‘Chaque polype est soutenu par une charpente siliceuse de 
spicules filiformes, disposés longitudinalement et & intervalles 
égaux sur la paroi interne de la cavité du corps.” (Proc. Zool. 
Soc. 1865, p. 663). 
The thickness of the elongated spicula of the axis is com- 
mensurate with the size of the entire coral, they being thin in 
the short young specimens, and thicker in the longer and more 
developed specimens. As they increase in length, they gra- 
dually become thicker by the deposit of fresh layers of sili- 
ceous matter on the outer surface, which is, doubtless, deposited 
by the flesh of the bark that surrounds each of the fibres; 
and new spicules also appear to be developed as the coral be- 
comes thickened, as there are intermixed between the thicker 
spicula thin ones of different degrees of thickness; but gene- 
rally they are of the same length as the rest. This seems to 
show that they are developed by the animal that lives in the 
bark, and are not shot out from the sponge at the base. But I 
might go on giving reasons without end, showing that the theory 
of those that believe the animal is a parasite is at variance with 
all parts of the organization of the coral and the animal that 
forms it. 
If we note the number of persons who have expressed an 
opinion on this subject, there is no doubt that the general opinion 
of zoologists, including some of high scientific reputation, as 
Valenciennes, Milne-Edwards, Max Schultze, Leidy, Bowerbank, 
and others, is against my view of the subject; but it is to be 
observed that I am supported by Professor Brandt and by Pro- 
fessor Barboza du Bocage, both of whom have paid great atten- 
tion to the subject, and have given the reasons for their belief ; 
while most of the others above quoted have only expressed an 
opinion, without giving the facts on which it is founded. 
I may add that, after much calm consideration of the ques- 
tion, and with the utmost willingness to change my opinion, if 
I found any evidence to induce me to do so, I still believe that 
the bark and the axis are parts of the same coral, and made by 
the same animal. In a former paper I observed that ‘the idea 
(that the bark of the coral is a parasite) requires the belief in 
the existence of two peculiar bodies which are always found to- 
gether and are unknown in any other state, instead of regard- 
