112 



COELENTERATA— ANTHOZOA 



PHYLÜM II 



Gregory and others. Here, as in Heliopora, the autopores are formed by 

 coalescence of numerous siphonopores in the coenenchyma. On the other hand 

 the corallites in the Heliolitidae have well-developed walls of compact homo- 

 geneous matter, and as a rule also tvvelve strong septa are present, sometimes 

 reaching nearly to the centre of the cylindrical Chambers. On account of 

 these differences the family has been separated from Heliopora, and some 

 authors have proposed to associate them with certain Hexacoralla, or with 

 the problematical Tabulata. 



Heliolites Dana (StelliporeUa Wenzel; Nicholsonia Kiär) (Fig. 175). Corallum 

 massive, nodular or ramose. Autopores with twelve more or less strongly 

 developed pseudosepta, though occasionally represented by rows of spinules, 

 and frequently with central columella. Siphonopores without septa, and 

 multlplying by fission or intermural gemmation. Abundant from Ordovician 

 to Devonian. 



Plasmopora E. and H. (Diploepora Quenst.). Like Heliolites, but having 

 walls of the siphonopores incomplete, and tabulae of contiguous tubes fused 

 together so as to form a vesicular tissue. Ordovician to Devonian. 





iyv. 



mMi"' 



Heliolites porosa Goldfuss. 



Devonian ; 

 enlarged 



Fig. 175. 



Eifel. ^, Corallum, natural size. iJ, Portion of outer sui 1 

 . C, Longitudinal section, enlarged. 



Profaraea E. and H. (Stylaraea E. and H., 7ion Seebach). Low incrusting 

 corallites, with relatively little coenenchyma. Tabulae present in the autopores. 

 According to Kiär, this form and Coccoseris Eichwald are closely related, and 

 perhaps identical. Ordovician and Silurian ; Scandinavia and North America. 



Cosmiolithes Lindstr. Corallites thin, lamelliform. Coenenchymal pores 

 thick-walled, not all of the same size, with concave or obliquely directed 

 tabulae. Autopores with well - developed septa. Silurian ; G. ornatus 

 Lindstr. 



Plasmoporella, Palaeoporites and Trochiscolithus Kiär. Silurian ; Scandinavia. 

 Acantholithus, Pycnolithus Lindstr. Eelated genera having the same distri- 

 bution. 



Appendix to the Anthozoa. 



Sub Order. TABULATA Milne Edwards and Halme. ^ 



Invaridbly composite coralla composed of tubiform or prismatic corallites. Walls 

 thick, independently calcified, compact or perforated hy connecting mural pores. Septa 



^ Literature : Lindström, O., Affinities of the Anthozoa Tabulata. Ann. Mag. Nat. Hist., 1876, 

 ser. 4, vol. xviii. — Nicholson, H. A., On the Structure and Affinities of the Tabulate Corals of the 

 Palaeozoic Period. London, 1879. — Roemer, F., Lethaea Palaeozoica, i., 1883, p. 416. — Waagen, 



