The corallites enlarge rapidly after having originated as buds.
The epitheca is very stout, and is strongly marked by transverse ridges and intermediate depressions.
The costae are visible on the upper surface of the corallum.
The calices are unequal, usually circular in outline, shallow, with stout margins. They project but slightly.
The columella is well developed and large.
The septa are in six systems, and there are three cycles of them in each. The primary and secondary septa are nearly equal, and reach the columella. The septa of the third cycle are small, and do not reach far inwards. The endothecal dissepiments are oblique and scanty.
Diameter of calices 1/20 to 3/20 inch.
The Solenastroeoe no longer inhabit the European seas, and no trace of them occurs in the dredgings of the North Atlantic Sea, of the Lusitanian coasts, and of the Mediterranean. They are not deep-sea forms, but are compound epithecate and exothecate corals suited for reef-building.
They abound in the reefs of the Red Sea, of the Indian and Great Ocean, and amongst the West-Indian reefs.
The fossil species have been found in the following localities : — Eocene — Fort Saint Pierre, Ghent*.
Oligocene — Monte Grumi, Montecchio Maggiore, Monte Viale, and Monte delle Carrioli, in the District of Castel Gomberto, in the Vicentin†.
Brockenhurst and Roydon, in Hampshire ‡.
Miocene — The Faluns, and Miocene of Turin and of Styria§. Miocene of Antigua || .
Raised Reefs — Red Sea % .
The new species differs from the Eocene type by having a well- marked columella, and in its septal arrangement.
Its small number of septa distinguishes it from the Oligocene forms.
The well-developed columella and the septal number associate the new species with the Miocene Solenastrcea turonensis, Ed. & H., of the Faluns, Turin, Styria, and Antigua, and with the recent S. Bournoni, Ed. & H., Antilles, S. Forskoelana, Ed. & H., Red Sea, S. sarcinula, Ed. & H., Indian Ocean, and S. Bowerbanki, Ed. & H., Singapore. The closest alliance is with the West-Indian recent
- Solenastroea Verhelsti, Ed. & H., is found amongst the Upper Miocene of
the West Indies.
† Solenastroea conferta, Reuss, and S. columnaris, Reuss, Pal. Stud, uber die alteren Tertiar. der Alpen. Wien. Akad. der Wissensch. 1867.
‡ Pal. Soc. Lond. P. M. Duncan, 1866.
§ Solenastroea turonensis, Ed. & H. Hist. Nat. des Corall. vol. ii. p. 488.
|| " Foss. Corals of West Indies," Quart. Journ. Geol. Soc. Dec. 1867, and previous papers.
¶ Solenastroea gibbosa, Ed. & H. op. cit. p. 496.
