4 82 



DISTRIBUTION OF RUGOSE CORALS. 



Fig. gi.^Lithostrotioii. 



Streptelasma, Palwophyllum, Siphoncuis, Favislella, Stauria, Micro- 

 plasma, Fletcheria, Omphyma, Darwinia, and the operculate corals 

 Goniophyllum and Rhizophyllum. But many genera range up to the 

 Devonian. Among such are Anisopliyllum, Ptychophyllum, Chono- 

 phyllum, Hallia, Aidacophyllum, Erido- 

 phyllum, Acervularia, Spongophyllum, 

 Strombodes, and Cystiphyllum, which has 

 the septa more or less rudimentary, so that 

 the coral is built up of vesicular tissue (tig. 

 90). Among peculiar Devonian genera are 

 Jlydrophyllum, Combophyllum, Microcy- 

 clus, Barypliyllum, Metriophyllum, Cras- 

 pedophyll'um, Pachyphylhim, and the oper- 

 culate Calceola. Several genera range 

 from the Lower Primary to the Carbon- 

 iferous, and among these are Petraia, 

 Cyathaxonia, Amplexus, Zaphrentis, Cya- 

 thopht/Uum, Diphyphyllum, C lisiophyllum, 

 which has a central tabulate structure dis- 

 tinct from the external structure, and 

 Strepliodes. Genera which range from 

 the Devonian to the Carboniferous include 

 Lophophyllum, Campophyllum, and Phil- 

 lipsastrcea. Carboniferous genera include 

 Menophyllum, Phryganophyllum, Pentaphyllum, Trochophyllum, Ca- 

 ninia, Lithostrotion, Koninckophyllum, Lonsdalia, Chonaxis, Dibu- 

 nophyllum, Ci/dophi/llum, Aulopliyllum, and Michelinia. Polyccelia 

 ranges through the Primary period. 



The Hexacoralla, or Zoantharia, comprises two principal groups ; 

 the Sclerobasica, which are compound organisms, not known prior 

 to the Tertiary rocks ; and the Sclerodermata, which includes the 

 majority of corals, both recent and fossil. This latter group has been 

 divided by Professor Martin Duncan, F.R.S., into Perforata, Fungida, 

 and Aprosa. 1 



Perforata is a type with the walls of the corallum porous or re- 

 ticulate. It is largely developed at the present day, and comprises 42 

 genera and 5 sub-genera. In the Palaeozoic rocks it is represented by 

 Favositipora, which is still living. Prisciturlen, Stylarcea, Calostylis, 

 and Somphopora are Lower Palaeozoic genera. Protarcea is Silurian 

 and Devonian, while Palceacis is Carboniferous. There is no recorded 

 Jurassic genus. The Cretaceous rocks yield Cyclobacia and Adino- 

 acis, Litharcea, which ranges to the Middle Tertiary, and Stephano- 

 phyllia, which stills survives. Dendracis and Stereopsammia are 

 found only in the Lower Tertiary ; and the following genera com- 

 mence in the Lower Tertiary, and still survive Ballanophyllia, En- 

 psammia, Endopacliys, Dendrophyllia, Madrepora, Astrceopora and 

 Porites. The Middle Tertiary yields Lobopsammia, and the following 



1 For Classification of the Madreporaria and Characters of the Genera, see 

 Duncan : Journal, Linn. Soc., Zoology, vol. xviii., Nos. 104-106, 1884. 



