Dr. J. E. Gray on the Fleshy Alcyonoid Corah. 117 



EXPLANATION OF PLATE XIII. 



Fig. 1. Dentition of Conns: a, one fang, with its muscle remaining' intact ; 



b, extremity of the other fang, more highly magnified, to show 



the barbed processes more distinctly. 

 Fig. 2. Dentition of Terebra. 



XIX. — Notes on the Fleshy Alcyonoid Corals (Alcyonium, 

 Linn., or Zoophytaria carnosa). By Dr. J. E. GrRAT, 

 F.R.S., V.P.Z.S.,&c 



This group of Corals was named Alcyonium by Linnaeus and 

 Pallas, but has been more lately subdivided into several ge- 

 nera. The polypes are social, generally with elongated 

 tubular bodies, which are united to one another into a more or 

 less fleshy crust or lobulated or branched coral. The inner 

 substance between the tubular bodies is sometimes rather 

 fleshy and permeated with vessels. The polypes and the flesh 

 are often strengthened with various-shaped calcareous, sunken 

 or superficial spicules ; but there is no central axis as in the 

 horny or stony Alcyonoid Corals. 



In one genus at least (Paralcyonium) the lateral younger 

 polypes arc short, and there is direct communication between 

 their bodies and the central cavity of the older or mother 

 polype ; and in some other genera, as Sympodiwm and Erythro- 

 jjoclium, which form only a thin crust, the body of the polype 

 is short, as in the animals that form a thin bark on the central 

 axis, e.g. in Gorgonia and Cor allium. 



The part of the polype at the base of the tentacles, and the 

 tentacles themselves, are often armed with a series of spicules 

 generally placed obliquely in two parallel series ; they pro- 

 tect the polype when it is protruded : in some these spicules 

 are so numerous as to prevent the complete contraction of the 

 polype. 



