ACTIXOZOA. 



229 



The important diversities of form in the polyp stocks are not 

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



F 



Fro. 17i. Vertical section through a polyp of Astroid/n 

 calycularia (after Lacaze Duthiera). The mouth open- 

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

 senteries fastened to the same ; also the calcareous 

 septa between the mesenteries, and the columella of 

 the skeleton, .S.t. 



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 Miean- 

 drinidce (fig. 179). 



The Anthozoa are all 

 inhabitants of the sea, 



Fio. J73. Vertical section 

 through the cup of Ci/athi- 

 na Cyat/ius (after Milno 

 Edwards). S, Septa ; P, 

 pali; C, columella. 



polyp, but are also the 

 resultant of varying 

 methods of growth by 

 gemmation and imper- 



Fia. 17fi. Ifnifivjiora verru- 

 coaa after Ed. H. 



FIG. 177. Branch of Octi- 

 Una sprciosa (after Ed . 

 H). 



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



