46 



BRITISH FOSSIL CORALS. 



and structure of the exotheca, in the method of gemmation, and in the septal develop- 

 ment. These distinctions render the division of the Brockenhurst Sohnastrcea into six 

 species absolutely necessary. This increase in the number of the species proves that the 

 genus must have been a large one ; and the resemblance of the specific forms to varieties 

 (from the really slight structural distinctions) is what is generally noticed in the case of 

 large genera. 



These new species belong to a division of the genus which is not represented else- 

 where ; it is characterised by the high septal number, the deficient columella, and the 

 amount of inclined endotheca. 



The recent Solenastraa are found in the Red Sea, the Caribbean Sea, and in the Indian 

 and Pacific Oceans. The horizontal endotheca and low septal number distinguish all 

 these species from those of Brockenhurst. 



The fossil species of the genus are Solenastraa Verhelsfi, Ed. and H., Solenastraa 

 Turonensis, Michelin sp., and Solenastraa composifa, Reuss sp. 



Solenastraa VerUehti is an Eocene form from Ghent ; and its rudimentary third cycle 

 of septa, very close corallites, and its paucity of slightly obhque and subconvex endotheca, 

 distinguish it at once and very decidedly. 



Solenastraa Turonensis has very long and close corallites with three cycles of septa and 

 a well- developed columella ; its very scanty and very feebly inclined endotheca, and the 

 wide-apart exothecal dissepiments, separate it from the form from Ghent, as well as from 

 those from Brockenhurst. MM. Milne-Edwards and J. Haime determine that this species 

 and Solenastraa composifa are identical. The Touraine form is of course from the Upper 

 Miocene. 



The following is a scheme of the classification of the Tertiary SolenastnecB : 



Solenastrcea, 



■with the coin- < 



mella 



OS -j; 



' The endotheca 

 greatly deve- 

 loped. 



The endotheca 

 not much de- 

 veloped. 



Five cycles com- 

 plete, or nearly 



Three cvcles 



Exotheca, banded 

 and cellular, in- 

 complete. 



fre- 



Exotheca very cellular and complete Cellulosa. 



> Gemmans. 



Granulata. 



Gemmation 

 quent 



Calices small ; 

 septa withpali- 

 form lobe 



Exotheca cellular and complete . 



Corallites partly covered vrith cellu- 

 lar and banded exotheca 



Corallites completely covered with 

 cellular exotheca 



Kueneni. 



> Reussi. 



> Beyrichi. 



Verhelsti. 



well developed. Three cycles of septa; corallites close ; endotheca ] „, 



slightly developed J 



