526 



RADIATES: POLYPS. 



Fig. 526. 



Fig. 524- 



Fig. 525- 



Artroides calycularis, Milne-Edw. 

 Coral of Fig. 523. 



Ocnlina horrescens, Ccenopsammia nigrescens, 

 Dana. Milne-Edw. 



The Genus Forties has the coral massive or branch- 

 ing, and the cells not over a line in diameter ; polyps 

 with twelve short tentacles. Fig. 519. The massive spe- 

 cimens are sometimes fifteen feet in diameter. 



MADREPORID.E, OR MADREPORE FAMILY.- -This Fam- 

 ily contains polyps which are not coral-producing at the 

 base, and hence the cells of the corallum are very deep, 

 and not crossed by septa within. The species are very 

 numerous, and the forms extensively varied. Fig. 518. 



The Sub-Order of Astrasacea contains polyps which are 

 mostly compound by budding or fissiparity, with well- 

 developed tentacles in multiples of six. It contains Litho- 

 phyllidae, Maeandrinidae, Eusmillidae, Caryophyllidae, Sty- 

 linidae, Astraeidae, Oculinidae, and Stylophoridae. 



M^ANDRINID^:, OR BRAIN-CORAL FAMILY.- -This Fam- 

 ily is well represented by the Genus Mceandrina, which 

 has the disks trench-like, sinuous, and the tentacles form- 

 ing a series along either margin. The form is generally 

 hemispherical, and from six inches to twelve feet in di- 

 ameter. Fig. 521. 



CARYOPHYLLID.E. This Family has the cells of the 

 coral with margin thin, and the coral within not trans- 

 versely septate. Fig. 520. 



