THE GORGONACEA OF THE SIBOGA EXPEDITION 



VIII. THE SCLERAXONIA 



C. C. NUTTING, 



Professor of Zoolog)', State I'niversity of Iowa. 



With 12 plates. 



(Aided by a grant from the Elizabeth Thompson science fund.) 



Section SCLERAXONIA Studer. 



(= PSEUDAXONIA von Koch.) 

 Scleraxojtia Studer. Versucli eines Systemes der Alcyonaria, i88S, p. 24. 



The definition of this section of the Gorgonacea, as given by Studer, is indicated in 

 the following translation : 



"Fixed, upright branched colonies in which the short polyp cavities are immersed in a 

 canal-bearing coenenchyma which contains numerous embedded spicules. The branches consist 

 of a cortical substance containing the polyps and a medullary substance which contains spicules 

 of different forms from those of the coenenchyma, densely aggregated and either connected by 

 a horny substance or bound together by a limestone sub.stance into a stony a.xis in which the 

 individual spicules are plainly evident". 



This definition, although correct, may be considerably shortened without losing its 

 effectiveness. Leaving out unessentials, the following will serve our purpose : 



Gorgonacea with an axis in which the individual spicules can be recognized and in 

 which they are connected into a more or less compact mass either by a horny substance or 

 calcareous matter. 



SIBOGA-EXrEUrriE Xlll/y'. 1 



