INTRODUCTION. Xl 
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 tabulee. 
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 trabicula, as is the case in Porites, or even 
perforated, excepting near their mner 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 1m- 
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 Cyathophyllide. The visceral chamber remains open 
from top to bottom, or is only subdivided by synapticule, or by irregular dissepiments, 
which extend from one septum to another without joining together, so as to form a series 
of distinct tabulee 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 Turbinolide, the 
Oculinide, the Astreide, and the Fungide ; 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: Psewdastreide and Pseudoturbinolide for example. 
Family I. 
TURBINOLID &. 
Milne Edwards and Jules Haime, Recherches sur les Polypiers; Annales des Sciences Naturelles, 
3™° série, tom. 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 
