ACTINOZOA.. 



220 



The important diversities of form in the polyp stocks are not 

 only occasioned by the differences of structure of the skeleton of the 



mm 



FIG. 175. Vertical section 

 through the cup of Cyathi- 

 na Cyathm (after Milne 

 Edwards). S, Septa ; P, 

 pali ; C, columella. 



polyp, but are also the 

 resultant of varying 

 methods of growth by 



FIG. 17L Vertical section through a polyp of Astroides gemmation and impei'- 

 calyoularis (after Lacaze Duthiers). The mouth open- 

 ing and cesophasreal tube are seen as well as the me- 

 senteries fastened to the same ; a 1 so the calcareous 

 septa between the mesenteries, and the columella of 

 the skeleton, Sk. 



feet fissioa. According 

 to the method, nume- 

 rous modifications of 

 branched stocks are dis- 

 tinguished, e.g., Madre- 

 pores (fig. 176), Oculi- 

 nidce (fig. 177), and the 

 lamellar and massive 

 stocks as Astrcea (fig. 

 178) and the Mcean- 

 drinidce (fig. 179). 



The Anthozoa are all 

 inhabitants of the sea, 

 and live mostly in the warmer zones, but certain types of the fleshy 



FIQ. 176. "Sladtvpora verrtt- 

 cosa after Ed. H. 



FIG. 177. Branch of Ocu- 

 lina speciota (after Ed. 

 H). 



