32 Prof. H. A. Nicholson on the 
strating the presence of the component spicules in any thin 
section of the skeleton of Corallium that I have prepared. 
The annexed sketch of part of a longitudinal section of a 
branch of Corallium will show that the skeleton is made up 
of spicules of the ordinary type of these structures amongst 
the Alcyonarians, the outline of the spicules being sometimes 
indistinct, and the interspaces between them being occupied 
by a peculiar crystalline tissue. Essentially similar pheno- 
mena are seen in transverse sections of the skeleton of Coral- 
lium. I may add that [ have also always found it possible 
to recognize the presence of the component spicules of the 
corallum even in the genus Js?s, though the fusion of the 
spicules is here much more complete than it is in Corallium. 
In fact, the spicules in Corallium are not, strictly speaking, 
fused,” any more than they are in T’ubipora. 
Part of a longitudinal section of Corallium rubrum, magnified 180 times, 
showing the spicules of the skeleton united by a crystalline or fibrous 
matrix, produced by the calcification of the soft interspicular tissues. 
In the second place, Mr. Hickson has made a series of very 
interesting investigations as to the endothecal structures of 
Tubipora, in which he shows that there is a much closer 
apparent resemblance between the axial tube of this genus 
and the infundibuliform tabule of Syringopora than I had 
been led to believe was the case by examining the specimens 
of the former genus at my disposal. He also shows that flat 
tabule, sometimes complete and sometimes incomplete, are 
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