SUBCLASS II 



HEXACORALLA 



105 



Family 1. Archaeocyathidae Walcott.^ 



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

 septal edges united by perforated interior wall, which encloses a holloio central space. 

 Synapticula present in interseptal loculi. 



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

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

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

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

 They represent possibly a distinct order of the Madreporaria. 



Family 2. Eupsammidae Milne Edwards and Haime. 



Corallum simple or becoming composite by lateral gemmation. Septa very 

 numerous, sometimes united by synapticula, and frequently with their inner edges 

 fused together. Theca naked or covered with epitheca, and formed by 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 



Fir.. 1(34. 



Eupsammiix 

 t r ch ifo nil is 

 (Pallas). Cal- 

 caire Gmssier ; 

 Chaussy, near 

 Paris. Natural 

 size. 



Fi<!. 105. 

 BalanophijUla siniiata Reuss. 

 Oligocene , Waldbockelheiiii, 



Prussia, a, Natural size ; 

 b, Number of septa enlarged. 



Fig. 166. 



StepTianophyUUi eleiians (Bronn). Pliocene ; 

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

 and lower surfaces, enlarged ; r-, Profile, natural 

 size. 



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.— TFa/co«, C. D., Bull. U.S. Geol. 

 Survey, No. 30, 1886. — Borneviann, J. G., Versteiiierungen des Canibrischeu Systems voii Sardinien. 

 1886. — Hinde, G. J., Quart. Journ. Geol. Soc, 1889, vol. xlv. — Lamhe, L. M., Revision of the 

 Genera and Sjiecies 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. 



