C(ELENTERATA. 



33 



epta rudimentary or abs 

 Tabulas well developed 



does not grow below a depth of 25 or 30 fathoms, and not in 

 water under a temperature of 66. 

 There are five suborders : 



Corallum hexameral. 



or absent. 



TABULATA. 



No tabulae TUBULOSA. 



Septa present. 



Corallum porous PERFORATA. 



Corallum imperf orate EPOROSA. 



Corallum tetrameral [Palaeozoic] EUQOSA. 



The Tabulata and the Rugosa have been placed by Cams among 

 the Hydrozoa, forming his group (?) Lithydrodea.* 



