41'2 Dr. J. E. Gray on the Arrangement of 



Fam. 2. Primnoadae. 



Axis inarticulate, solid. Bark formed of flat imbricate scales. 

 Polype-cells prominent, covered with imbricate scales. 

 Primnoa. ^ Callogoryia. y Primnoella. 



tt ^<*'«^ articulated. 

 Fam. 3. Melitaeadse. 



Axis spongy, permeated by flexuous tubular canals inter- 

 rupted by harder, swollen, calcareous joints. Bark granular; 

 cells in series on the edge of the branchlets. 



Melitaa. MopseUa. fSulanderia. 



Fam. 4. Isidese. 



Axis calcareous, solid, divided by narrowed horny joints. 

 Bark granular, with irregular-shaped spicula. 

 Isis [Cynosaire). Isidella. Mopsea. 



Suborder II. Ceratophyta. 



Coral arborescent, supported by a continuous (or jointed ?) 

 horny axis, which does not effervesce in muriatic acid. 



Fam. 1. Gorgoniadse. 



Bark granular, persistent, with sunken irregular-shaped 

 spicula, with a more or less distinct groove down each side, and 

 with the cells in series on each side of the branchlets. 



* Coral arborescent or reticulated -, cells on side of the branchlets. 



Gorgonia. Arborescent ; branchlets subcompressed ; cells on 



side, moderate. 

 Pterogorgia, Arborescent; branchlets much compiessed; cells 



minute, on edge. 

 Rhipidogorgia. Reticulated, fan-like ; cells on sides. 



** Coral frondose ; cells on surface of frond. 



Hymenogorgia. Axis branched, filiform, branches separate. 

 Phyllogorgia. „ „ branches netted. 



Phycogorgia. Axis expanded, foliaceous, thin. 



Fam. 2. Plexauridae. 



Bark granular, persistent, cork-like, without any impressed 

 lateral grooves. Cells placed equally on all sides of the branches. 

 Plexaura (Bebryce). Cells not raised, simple. 

 Rhinogo7'gia. Cells not raised, bounded by a conical process. 

 Eunicea, Cells more or less produced, simple. 

 Gonidora. Cells convex; mouth radiated. 



