ALCYONARIAN CORALS 135 



careous sponges, but when it is combined with a system of 

 regular monomorphic tubes the balance of evidence turns 

 down the Alcyonarian side of the scale. 



The examples of Alcyonaria described in the preceding 

 pages are not arranged in their zoological order, and the 

 following table is added to indicate to the student the system 

 of classification and the position of these examples in the 

 group. 



(3rder I. — Stolonifera. Primary polyps springing in- 

 dependently from a membranous or ribbon-like axis. 



Tubipora. 

 Telesto. 



Order II. — Alcyonacea. Colonies without an axis, 

 spongy in texture. 



Alcyonium. 

 Sarcophytum. 



Order III. — Coenothecalia. Colonies without an axis, 

 stony in texture. 



Heliopora. 

 Ceratoporella ? 



Order IV. — Gorgonacea. Colonies with an axis. 



Sub-order A. — Pseudaxonia. Axis perforated 

 by canals or solid and ston}'. 

 \\'rightella. Corallium. 

 Paragorgia. Melitodes. 



Sub-order B. — Axifera. Axis solid, horny, or 

 horny and calcareous. 

 Gorgonia. Plexaura. 

 Isidella. Primnoa. 

 Isis. Pterogorgia. 

 Juncella. Rhipidogorgia. 

 Leptogorgia. Xiphigorgia. 



