SUBCLASS III 



ALC YON ARIA 



111 



Family 5. Helioporidae Moseley.^ 



Calcareous corolla, composed of two series of tuUform corallites ; the larger tubes 

 {antopores) are embedded in a strongly developed coenenclujma made up of smaller 

 tubes {siphonopores). Both autopores and siphonopores are closely tabulate; the 

 autopores are provided with ridge-like pseudosepta, which, however, do not correspond 

 numerically with the tentacles. 



The affinities of the Helioporidae with the Alcyonaria were first pointed out 

 by Moseley. The larger polyps inhabit the autopores, and are furnished with 

 eight mesenterial folds and a crown of eight tentacles ; while the smaller 

 polyps, which are without either tentacles or sexual organs, are lodged in the 

 siphonopores. The skeleton is composed of calcareous trabeculae, the same as 

 in the Hexacoralla, from whose centres of calcification radial fibres extend 

 outwards in caespitose fashion. The siphonopores multiply by intermural 

 gemmation, while the autopores 

 are formed by the coalescence 

 and fusion of a number of the 

 siphonopores. JS^'o:^;^^^^ 



Heliopora Blainv. {Fig. 174, fe^-^^V 



Corallum massive or 

 ramose; autopores with 12-25 

 slightly developed pseudosepta, 

 and embedded in a coenen- 



chyma made up of smaller f,o. 174. 



the latter are 

 tabulate than 



Heliopora iMTtsi-hl (Renss). Upper Cretaceous; St. Gilgen on 

 Wolfgangsee, Salzkammergut. ,4, Corallum, natural size. i>, Por- 

 tion of surface, enlarged. <', Poh/tremacis blainvUleana Reus.s. 

 Cretaceous to upper Cretaceous ; Gosau, Salzkammergut. Vertical section, 

 enlarged. 



siphonopores : 

 more closely 

 the autopores. 

 Recent, 



Polytremacis d'Orb. (Fig. 174, C). Like Heliopora, but pseudosepta much 

 more strongly developed, sometimes reaching nearly to the centre. Cretaceous. 



Octotremacis Gregory (Polysoleiiia Eeuss non Ehrenb.). Miocene; Java. 



Family 6. Heliolitidae Lindstrom.- 



Corallum. massive, more rarely ramose, varying from spheroidal to Jiahellate, 

 composed of tubular or vesicular coenenchyma enclosing corallites in the form of large 

 cylindrical and numeroiis smaller angular cells ; both the macro- and microcorallites 

 with tabulae. Usually tivelve septa present in the large cylindrical cells, but these 

 are often r%idimentary. No mural pores; basal epitheca present. Silurian and 

 Devonian. 



The genera assigned to this family exhibit in their general appearance, 

 finer structure and manner of multiplication, considerable resemblance to 

 Heliopora, with which they were associated by Moseley, Nicholson, Bourne, 



^ Moseley, II. N., The Structure and Relations of Heliopora eaerulea. Philos. Traus. Roj^al 

 Society, 1877, vol. clxvi. — Bourne, G. C, On the Structure and Affinities of Heliopra caernlea. 

 Ibid., 1895, vol. clxxxvi. pt. 1. 



'^ Lindstrbm, G., Remarks on the Heliolitidae. K. Svensk. Vetensk. Akad. Handl. , 1899, 

 vol. xxxii. — Kiar, J., Die Koralleufauna der Etage 5 des norwegischen Sihirsystems. Palaeontogr. 

 1899, vol. xlvi. — Idem, Revision der mittelsilurischen Heliolitiden, etc. Videnskabs-Selskabets 

 Skrift. I. Classe, No. 10, 1903. 



