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 So/enastree 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 Solenastre@e@ 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 Solenastrea Verhelsti, Hd. and H., Solenastrea 
Turonensis, Michelin sp., and Solenastrea composita, Reuss sp. 
Solenastrea Verhelst: is an HKocene form from Ghent; and its rudimentary third cycle 
of septa, very close corallites, and its paucity of slightly oblique and subconvex endotheca, 
distinguish it at once and very decidedly. 
Solenastrea Turonensts 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 Solenastr@a composita are identical. 'The Touraine form is of course from the Upper 
Miocene. 
The following is a scheme of the classification of the Tertiary Solenastree : 
Exotheca very cellular and complete Cellulosa. 
Gemmation fre- \ Giauke 
5 The endotheca | Exotheca, banded quent . . : 
S greatly deve- } and cellular,in- ’ Go); 005 small: 
ee | Fa loped. complete. septawith pali- + Granulata. 
s | S$’ form lobe 
Saieanee § SS The  endotheca 
ae ihe ae 2 \ 0 not much de- | Exotheca cellular and complete. - Koeneni. 
Saath 2 = veloped. 
Corallites partly covered with cellu- \ Rouse 
Five cycles com- lar and banded exotheca 
plete, or nearly : ef face: 
sO. Corallites completely covered wit ae 
cellular exotheca | Beyrichi. 
Three cycles. : " : : : : : . Verhelsti. 
well developed. Three cycles of septa; corallites close ; endotheca 
slightly developed } Duronensis. 
