SÜBCLASS II 



HEXACORALLA 



10^ 



Family 1. Archaeocyathidae Walcott.i 



Simple, turhinate, or sub-cylindrical coralla. Septa and theca porous ; inner 

 septal edges united hy perforated interiar wall, which encloses a hollow central space. 

 Synapticula present in interseptal loculi. 



All biit one of the genera described up to the present time (Archaeocyathus 

 Bill., Ethmophyllum Meek, Spirocyathus Hinde, Protopharetra Bornem., etc.) 

 occur in the Cambrian rocks of North America, Spain, Sardinia and Aus- 

 tralia. Aükokania Walcott is known from the Lower Huronian of Ontario. 

 They represent possibly a distinct order of the Madreporaria. 



Family 2. Eupsammidae Miliie Edwards and Haime. 



Corallum simple or hecoming composite hy lateral gemmation. Septa very 

 numerous, sometimes united hy synapticula, and frequently witli their inner edges 

 fused together. Theca naked or covered with epitheca, and formed hy thickening of 

 the septal edges. Silurian to Recent. 



Calostylis Linds. Corallum simple, sub-cylindrical, or composite and 

 multiplying by lateral gemmation. Septa very numerous, of spongy con- 

 sistency, and either fused together or united by synapticulae. 

 Columella thick, spongy ; wall covered with epitheca. Silurian ; 

 Gotland. This genus probably belongs to the Tetracoralla. 



Haplaraea Milasch. Simple, cylindrical coralla, with broad 



Fio. 164. 



Eupsammia 

 t rochtformis 

 (Pallas). Cal- 

 caire Grossier ; 

 Chaussy, iiear 

 Paris. Natural 

 size. 





I 



'^^^^»sf^ist 





Fig. 165. 

 Eahuwphyllia sinuata Reuss. 

 Oligocene , Waldböckelheiin, 

 Prussia. a, Natural size; 

 b, Number of septa enlarged. 



Fig. 166. 



Steplumophyllia elegans (Bronn). Pliocene ; 

 Stazzano, near Modena, Italy. a and h, Upper 

 and lower surfaces, enlarged ; c, Profile, natural 



encrusting base. Septa numerous, extending to the centre, perforated 

 by large apertures, and sometimes fused together or united by synapticulae. 

 Dissepiments also present, but no columella. Jurassic and Cretaceous. 



Eupsammia 'E. and H. (Fig. 164). Conical or turbinate, acutely pointed, 

 free. Septa very numerous, arranged in five cycles, those of the last cycle 

 stouter than the rest. Columella present or absent. Eocene to Recent. 



Balanophyllia Wood (Fig. 165). Simple, sub-cylindrical, attached by 

 the base. Columella spongy ; septa closely crowded, partly fused together. 

 Eocene to Recent. 



Stephanophyllia Mich. (Fig. 166). Simple, discoidal; base horizontal, calice 



1 Billings E., Palaeozoic Fossils of Canada, i., 1861-65.— WWc-o^^, C. D., Bull. U.S. Geol. 

 Survey, No. 30, 1886.— ßor7iema?iw, /. G., Versteinerungen des Canibrischen Systems von Sardinien. 

 \%%Q.— Hinde, G. J., Quart. Journ. Geol. Soc, 1889, vol. x\v.—Lambe, L. M., Revision of the 

 Genera and Species of Canadian Palaeozoic Corals. Geol. Surv. Canada, Contrib. to Canad. Palaeont., 

 1899, vol. \\.— Taylor, W. T. G., The Archaeocyathinae. Mem. R. Soc. S. Aust., 1910, vol. ii. 



