THE COELEXTERATA 



257 



A. 



B. 



Fig. 161. Examples of Zoantharia. 



A, Oculina speciosa, & branch of madreporarian coral. (After Sedgwick). 



B, Meandrina, a rose-coral of the order Madreporaria. (After Weysse). 



C, A group of sea anemones. (After Andres). 



used in jewelry. The latter is known as Corallium of the order Gor- 

 gonacea. 



Sub-class II. Zoantharia (Fig. 161). These usually possess many 

 simple, hollow tentacles, generally arranged in multiples of five or six. 

 There are two siphonoglyphes as a rule, and the mesenteries vary in 

 number. The retractor muscles are never arranged as in the Alcyonaria. 

 A skeleton may or may not be present. The animals may be simple or 

 colonial. 



Examples of Zoantharia are the sea-anemones such as Actiniaria, 

 and the stony corals such as Oculina of the order Madreporaria, and the 

 rose-coral Meandrina, order Madreporaria. 



