INTRODUCTION. xi 



Sub-order 1. 

 ZOANTHARIA APOROSA. 



Corallum composed essentially of lamellar dermic sclerenchyma, with the septal ap- 

 paratus highly developed, completely lamellar, and primitively composed of six elements ; 

 no tabulae. 



The foliaceous or lamellar structure of the calcified tissue, which furnishes one of the 

 principal characters of these Corals, is always recognisable in the exterior part of the septa ; 

 these organs are never composed of irregular trabiculae, as is the case in Porites, or even 

 perforated, excepting near their inner margin. The walls are also very seldom porous, and 

 usually constitute an uninterrupted theca, so as to admit of no communication between the 

 visceral chamber and the exterior, except by the calice. The septa form the most im- 

 portant part of the Polypidom ; they augment more or less in number as the Polyp rises, 

 but in general remain unequally developed, and are disposed in groups corresponding to 

 the six primitive radii, or to a multiple of that number, but never present a quaternary 

 arrangement, as is often the case in Cyathophyllidae. The visceral chamber remains open 

 from top to bottom, or is only subdivided by synapticulae, or by irregular dissepiments, 

 which extend from one septum to another without joining together, so as to form a series 

 of distinct tabulae or discoid floors ; a mode of structure which is on the contrary prevalent, 

 and very remarkable in most of the Corals belonging to our third and fourth sections. 



The Zoantharia aporosa are the most lamelliferous and stelliform of all the Corallaria ; 

 they are very numerous, and belong to four principal families : the Turbinolidce, the 

 Oculinidce, the Astreida, and the Func/ida ; but some few of them cannot find a proper 

 place in any of these natural divisions, and appear to constitute a certain number of satellite 

 or transitional minor groups, which partake of some of the characters of two or more of the 

 above-mentioned principal forms, without possessing any structural peculiarity of sufficient 

 importance to make us consider them as the representatives of a special type ; these groups 

 are therefore not of the same zoological value as the preceding, and in order to point out 

 their aberrant nature, we shall designate them by names indicative at once of their principal 

 affinities and their dependent character : Pseudastreidce and Pseudoturbinolidce for example. 



Family I. 

 TURBINOLIDCE. 



Milne Edwards and Jules Haime, Recherches sur les Polypiers ; Annales des Sciences Naturelles, 



3 me serie, torn, ix, p. 211, 1848. 



Corallum in general simple, never fissiparous, and multiplying by lateral gemmation in 

 compound species. Interseptal loculi extending from the top to the bottom of the visceral 



