454 CLASSIFICATIONS OF ZOOPHYTES. 



Tethya. 



Halicliondria. ; 



Spongia. 1 



Grantia. ( 



II. Cellulifera. 

 Polypi lodged in calcareous cells imperforate at the base. 



A. Substance rigid, stony. 



I. Cells in tlie form of minute pores, imbedded. — Mille- . 



PORAD^. \ 



Millepora. j 



II. Cells tubular, and produced beyond tbe surface.— Tubi- j 



PORAD^. 



Tuhipora. \ 



Favosites. j 



Tubulipora. i 



Discopora. 



Filipora. 



Terehellaria. 



III. Cells utriculur, adjacent, or superimposed. — Escha- 



RAD-E. 



Escbara. 



Retepora. 1 



Cellepora. 



Berenicea. \ 



Hippothoa. J 



Alecto. 

 A A. Suhstance flexible. — Flustrad^. 



Farcimia. ; 



Flustra. \ 



III. Thecata. I 



Polypi surrounded by a membranaceous tube, covering the | 



subdivisions of their compound body. I 



A. Sheath slightly calcareozis ; cells single, or in roivs. j 



I. Sbeath sligbtly calcareous, cells enlarged, in rows, united or j 



single. — Cellariad^. | 



a. Cells united. ^ 



b. Cells witb tbe oi'ifices opening on the upper surface. I 



Cellularia. i 



Tricellaria. 



Crisia. , 



