294 Dr. J. E. Gray on the "Glass-Rope " Hyalonema. 



" L^aspect granuleux^ chagrin^, que presente la surface exte- 

 rieure du corium et des polypes n'est pas le resultat d'une simple 

 incrustation de detritus de sable (comme on I'affirme pour les 

 individus du Japon), mais il est du h la presence d'un nombre 

 infini de spicules reguliers, en forme de massue et herisses de 

 pointes. Ces spicules font partie integrante de la couche la 

 plus exterieure ou tegumentaire. 



*' Chaque polype est soutenu par une charpente siliceuse de 

 spicules filiformeSj disposes longitudinalement et h, intervalles 

 egaux sur la paroi interne de la cavite 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- 



