SUB-CLASS III 



A N T I fOZOA OCTOCORALLA 



107 



lv ;i tibro-crystalliiH' calcareous matrix impregnated with organic matter. It 

 is found hut rarely in tin- fos>il state, hut is known from the ( Yetaceous and 

 Tertiar. 



Family 4. Tubiporidae. MiliK--l'Mwanl< ami 



/' red-coloured /////// calcar&nu tofas conntctrf by 



plot 



The cylindrical tubes of the remit Or^anpipe Coral (7 ? ///;//w//v/) are com 

 posed of spiniform sck-rites, which are united with one another directly in sueli 

 nianner as to enclose small hollow spaces appearing superficially as pores. The 

 connecting horizontal plates or floors a re traversed by canals which communicate 

 with tin- \ isreral diamliers of the tubes by means of numerous round openings ; 

 ne\\ coi-allites are luidded from their upper surfaces. Unknown in fossil state. 



Family 5. Helioporidae. Moseley. 



of two series of tubifonn condlites ; the larger tubes 

 are embedded in a strongly developed coenenchyma nmde up of *./>/"//</ 

 (siphonopores). Both autopores and siphonopores are closely tabulate; the 

 are provided with ridge-like pseudosepta, which, however, do not n>m>*pinnl 

 numerically with the tentacle. 



The affinities of the Helioporidnc with the Octocoralla were first pointed out 

 by Moseley. 1 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 A J: c 



tentacles or sexual organs, are 

 lodged in the siphonopores. The 

 skeleton is composed of cal- 

 careous trabeculae, the same as 

 in the ]Ic.i-in-nrnll(i, from whose 

 centres of calcification radial 

 fibres extend outwards in caespi- 

 tose fashion. The siphonopores 

 multiply by intermural gemma 

 tion, while the autopores are 

 formed by the coalescence and 

 fusion of a number of the siphono- 

 pores. 



Heli/>rn, niainv. (Fig. 191, A, B). Corallum massive or ramose ; autopores 

 with 12-25 slightly developed pseudosepta, and embedded in a coenenchyma 

 made up of smaller siphonopores; the latter are more closely tabulate than the 

 autopores. Cretaceous to Recent. 



Polytremanx, d'Orb. (Fig. 191, (.'). Like Helioporv, but pseudosepta much 

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



Certain Palaeozoic corals (Heliolitidne} exhibiting characters very similar to 

 IHlniHH-ii are assigned to the same vicinity with the latter by Moseley, 

 Nicholson, and other authors. Like Heliopoi'a, the corallum in these forms i- 

 massive, and consists of larger tubes embedded in a coenenchyma formed of 





Fro. 



Rcuss sp. 



101. 

 Upper Cretaceous 



St. 



Beuw. Upper Crateceoiu 



sectiou> enlarged< 



Oown, saizkiumncr-ut. Vertical 



1 Moseley, If. A"., Philosophical Transactions, Royal Society, vol. 166, 1877. 



