CH. VI MARINE FAUNA OF TALISSE SHORES 125 



transverse plates. The precious coral of commerce {Coral- 

 Hum rubrum) belongs to this order ; but it is never found 

 in warm tropical waters. The remaining Alcyonarians 

 possess a skeletal support of loose spicules disconnected 

 with one another, which, when the soft parts are dissolved 

 away, fall to the ground as fine granules of hme. Many 



Fig. 16. — Clavularia viridis, an Aloyonarian coral growing upon a dead 

 branch of a Madrepore. 



of the Alcyonarians, however, are supported by other 

 skeletal substances than hme. The flexible corals {Gor- 

 gonidce), for example, possess a sohd core of horny sub- 

 stance, and several of the creeping stoloniferous Alcyonarians 

 have their walls strengthened by a hard horny substance 

 of uncertain chemical af&nities. 



