472 RADIATA: POLYPI. 



wiien the polyps die, wither, and disappear that we see 

 the solid coral itself. 



Polyps grow in various and most wonderful and beauti- 

 ful forms, imitating almost all kinds of vegetation, lichens, 

 fungi, mosses, ferns, herbs, shrubs, and trees. A hundred 

 years ago, or more, they were thought to be plants ; and 

 even Linnaeus regarded them as plant-animals, that is, 

 partaking of the character of both plants and animals ; 

 but naturalists now regard them as true animals, although 

 they are often called Zoophytes, a word which means 

 Animal-plants. 



The colors of these wonderful animals of the sea are as 

 beautiful and almost as varied as their forms ; and some 

 of the polyp communities equal, in splendor of colors, 

 the most beautiful flower-gardens of the land. Even beds 

 of daisies, pinks, and asters have their rivals beneath the 

 waves of the sea. 



According to Professor Yerrill, the Polyps may be 

 divided into three groups or Orders, thus : * 



1. ALCYON"ARIA or polyps with eight long fringed tentacles 



around a narrow disk ; as "Sea-Pens," Gorgouias or "Sea- 

 fans," Red Coral, Organ-pipe Coral, etc. 



2. ACTINARIA or polyps with very numerous tentacles, and in 



most cases with a perfectly soft body ; as Sea-anemones. 



* In Professor Dana's splendid book, "Corals and Coral Islands," the 

 Polyps are grouped thus : 



1. AOTINOID POLYPS or the Sea-anemones and the Coral-producing polyps 



related to the Sea-anemones in their tentacles and in their interior 

 structure. The septa and tentacles are in multiples of six. 



2. CTATIIOPHYLLOID POLYPS or those like the Actinoids in their tentacles 



and interior structure, except that the number of tentacles and 

 interior septa is a multiple of four. They were the earliest of pol- 

 yps, and the most abundant of all in the Paleozoic ages. 



3. ALCYONOID POLYPS or those having eight fringed tentacles ; as the 



Gorgouias and Alcyouia. 



