PALAEOZOIC 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 Acthiozoa, as 

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

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

 duction, 1850; and Polypiers Eoss. des Terr. Pal., 185 1). In 

 this division was included a large assemblage of Corals, ranging 

 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 Erench 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 Astrmda; by not being 

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

 zontal divisions extending from side to side of the general 



A 



