96 ' COELENTERATA—ANTHOZOA SUB-BRANCH II 
Sub-Family C.  Porirrmyar. Milne-Edwards and Haime. 
Septa not very numerous, well developed.  Corallites united by their porous walls. 
Litharaea, BE. and H. (Fig. 170). Massive coralla. Calices sub-polygonal ; 
septa generally in three cycles ; columella spongy. Eocene and Miocene. 
Ihodaraea, E. and H. Massive coralla. Spurious walls of corallites thick ; 
pali prominent. Miocene and Recent. 
Porites, Lam. (Fig. 171). Massive or branching coralla. Calices shallow, 
polygonal ; septa irregularly reticulated ; columella papillous, surrounded by 

Fic. 171. a, Alveopora spongiosa, Dana. Recent; Fiji Islands. 
Porites incrustans, Reuss. Miocene ; Longitudinal section of corallite showing perforate walls 
Moravia. a, Transverse section ; and tabulae ; b, Alveopora rudis, Reuss. Nummiaulitie lime- 
b, Longitudinal section. Both figures stone ; Oberburg, Styria, 1/;; c, Calices, greatly enlarged. 
highly magnified. (Fig. a, after Dana; b, after Reuss). 
single cycle of pali. Cretaceous to Recent. The genus Porites is one of the 
most important of existing reef-builders. 
Protaraea and Stylaraea, E. and H. Usually enerusting coralla with poly- 
gonal calices. Visceral chambers partitioned off by horizontal tabulae. Silurian 
and Devonian. 
Sub-Family D. ALveoporiINnakE. Verrill. 
Septa composed of detached trabeculae, spines, or reticulated lamellae. Theca 
perforate. Visceral chamber with perforate tabulae. 
Alveopora, Quoy and Gaim. (Fig. 172). Massive coralla. Calices small, 
polygonal. Septa represented by detached spinous processes. Tabulae sparsely 
developed, remotely situated. Tertiary and Recent. 
Koninchia, E. and H. Cretaceous. 
Family 5. Madreporidae. Dana. 
Composite, branching, or lobate coralla with small tubiform corallites embedded in 
a canaliculated and reticulated coenenchyma. Septa (6-12) sometimes imperfectly 
developed. Two long septa projected from opposite sides and meeting in the centre. 
The genus Madrepora, Lin. (Fig. 173), is an important agent in the con- 
5 ) 5 e4) a o 
struction of existing coral reefs, and builds colonies sometimes of considerable 
size. It occurs sparsely in the fossil state in the Tertiary. 
Range and Distribution of the Hexacoralla. 
The group Aporosa of the Hexacoralla appears to have originated from the 
Tetracoralla, and to form the direct continuation of their line. They begin as 
