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the soft bark, become cemented together by the cement substance which is at first horny but 
subsequently becomes calcified and that the important difference, as regards the axis, between 
the Sclerogorgiide and the Coralliide is that in the former family the cement substance does 
not becomes calcified in the latter it does. The axis of other members of the Pseudaxonia 
differs from that of these two families in being porous or lacunar'). As regards the origin of 
the cement substance we have little or no direct evidence, but the evidence of comparative 
anatomy suggests very forcibly that it is not formed by the activity of the scleroblasts but by 
a modification of the chemical character of the mesogloea. 
The expression used by Wriscut and STUDErR (7) that *the axis of Sclerogorgiide is 
formed of a tissue consisting of numerous closely intercalated elongate spieules with dense 
horny sheaths’” suggests that the cement substance is formed by a fusion of previously 
distinct sheaths formed by the scleroblasts. The evidence afforded by KörLıkEr distinctly 
contradicts this hypothesis, but supports the view that it is formed from mesogloea. How the 
mesogloea is changed chemically is unknown. The amount of organic matter retained in it 
when the calcification is completed is very small and the nuclei of mesogloeal cells, if they are 
present, have hitherto escaped notice. It is clearly incorrect, from these observations, to describe 
the axis of the Coralliide as the “result of spicules fused together’. 
Dimorphism. The colonies of Coralliidae are dimorphie. MoseEL£y (5) was the first 
to call attention to the dimorphism of Corallium nobile a feature of this species which was 
overlooked or misunderstood by DE LACAZE-DUTHIERS. KısHInouvE (3), has proved that Corallıum 
japonicum, C. konojoi, C. inutile and C. elatius are dimorphic. I can also state from the 
examination of a specimen from off the Irish coast that C. johnstoni is dimorphic. A curious 
point of difference between Corallium nobile of the Mediterranean Sea and the other species of 
the genus is to be found in the fact that the sexual organs are found only in the autozooids of 
Corallium nobile whereas they are found only in the siphonozooids of those species mentioned 
above that have been carefuliy examined. DE LacazE-DurHiers’ description and figures are 
conclusive on the first point as regards Corallium nobile, but I have confirmed them by the 
examination of a series of sections through a piece of coral from Naples kindly given to me by 
Dr. Epırın Prarr and I may add that I can find no trace of sexual cells in the siphonozooids. 
I have confirmed Kısmmovve’s statement that in C. e/atius, the siphonozooids bear the gonads 
but the specimen of C. Johnston! 1 examined was unfortunately in a condition which renders it 
impossible for me to state definitely that the autozooids do not bear the gonads. 
Corallium Lamarck. 
Madrepora (pars) Linnaeus, Syst. Nat., X, 1757. 
/sis (pars) Linnaeus, System Nat. XII. 
Corallium Lamarck, Mem. Mus. Hist. Nat., I, 1815. 
Corallium + Pleurocorallium + Hemicorallium Gray, Catologue of Lithophytes, 1370, p. 22. 
Corallium + Pleurocorallium Ridley, Proc. Zool. Soc., 1882, p. 221. 
Corallium + Pleurocorallium -- Pleurocoralloides Moroff, Zool. Jahrb. Abth. System., 1902, p. 404. 
Corallium Kishinouye, Journ. Imp. Fisheries Bureau Japan, XIV, I, 1904, p. 20. 
I) According to KÖLLIKER p. 144 there are lacun® in the axis of Sclerogorgia itself. 
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