PALEOZOIC TABULATE CORALS. 



CHAPTER I. 



THE CLASSIFICATION AND AFFINITIES OF THE " TABULATE 



CORALS." 



The " Tabulata',' as originally understood, constitute one of 

 the four primary divisions of the Zoantharian Actinbzoa, as 

 laid down and defined by Milne- Edwards and Haime in their 

 great works upon the fossil Corals (Brit. Foss. Corals, Intro- 

 duction, 1850; and Polypiers Foss. des Terr. Pal., 1851). In 

 this division was included a larcre assembla8;-e of Corals, rancrlne 

 from the Silurian period to the present day, and often of very 

 diverse structure, but characterised by the possession of well- 

 developed " walls," by the separation of the visceral cavities 

 of the corallites into distinct chambers by transverse partitions 

 or " tabulae," and by the rudimentary condition of the " septa." 

 The distinguished French zoophytologists just quoted remark 

 of this division of the Corals, that its principal character " is 

 founded on the existence of the lamellar diaphragms that close 

 the visceral chamber of the corallites at different heights, and 

 differ from the dissepiments of the Asti'ceidcE by not being 

 dependent on the septa, and forming as many complete hori- 

 zontal divisions extendinfy from side to side of the general 



