SUB-CLASS II HEXACORALLA—PORITIDAR ~— 95 
Family 4. Poritidae. Dana. 
Composite coralla composed of porous sclerenchyma. Corallites small ; septa as 
rule only moderately numerous, sometimes represented by rows of trabeculae or lamellae. 
Theca absent. 
Sub-Family A. SponcGioMoRPHINAE. Frech. 
Corallum composed of thick trabeculae and strengthened by horizontal synapticulae. 
Calices very imperfectly differentiated from coenenchyma, and without distinct septa. 
Dissepiments usually sparsely developed. 
Of the genera belonging to this sub-family, Spongiomorpha, Heptastylis, and 
Stromatomorpha, Frech, are found in the Alpine Trias (Rhaetic and Zlambach 
Schichten). These are all tuberous, composite coralla of extremely irregular 
form. In Spongiomorpha and Heptastylis, six septa are indicated by somewhat 
regularly disposed columns of trabeculae; and in the latter form these are 
bound together by synapticulae which are projected at equal altitudes, and 
form perforated horizontal storeys. In Stromatomorpha no radial arrangement 
of the trabecular septa exists. 
Palaeacis, BK. and H. (Sphenopoterium, Meek and Worth), occurring in the 
Carboniferous limestone of North America and Scotland, possibly also belongs 
here. 
Sub-Family B. Turpryartyar. Milne-Edwards and Haime. 
Septa well developed, compact.  Corallites embedded in canaliculated coenenchymu. 
Actinacis, VOrb. (Fig. 169). Massive or branching coralla. Coenenchyma 
abundant, granulated ; septa stout, of nearly uniform proportions, columella 
papillous ; pali in front of all the septa. Cretaceous and Tertiary. 

Fic. 169. 
Fic. 170. 
Actinacis elegans, Reuss. Upper Cretaceous ; Gosau 
Valley, Salzkammergut. o«, Upper surface, natural Litharaea Websteri, Bowerb. sp. Eocene; Brackles- 
size ; b, Transverse section, enlarged; c, Longitudinal ham Bay, England. a, Corallum, natural size; b, Fou 
section, enlarged (after Reuss). calices enlarged. 
Astraeopora, Bly. Massive coralla. Coenenchyma porous and on upper 
surface echinulate. Septa of dissimilar proportions ; columella and pali absent. 
Tertiary and Recent. 
Dendracis, E. and H. ; Cryptaais, Reuss. Tertiary. 
Turbinaria, Oken (Gemmipora, Bly.) Corallum foliaceous. Coenenchyma 
tolerably compact and finely echinulate. Septa of similar proportions ; 
columella spongy. Cretaceous to Recent. 
