only in the Cyathophyllidee, but also in the Milleparidw, Faro sitida, and other palteozoic families. Of the 129 Silurian corals, 121 belong to the tabulated divisions.
The Devonian system contains about 150 described corals, the carboniferous limestone 76, and the magnesian limestone only 5 or 6. The commonest forms of simple, turbinatecl corals, are Cyathophyllunt (fig. 4, 2 and 3), which exhibits four slight fossulcc in its cup, and is often supported by root-like processes. In Zaphrentis (fig. 4, s) there is but one deep fossula. Amplexus (fig. 4, i) is a characteristic carboniferous fossil, nearly cylindrical, and often so straight and regular in its growth as to have been originally described as a chambered shell. The radiating septa are very slight, and the horizontal partitions simple, flat, and almost as regular as the septa of the Orthoe,cras. In the Silurian Cystiphyllum (fig. 4, 4) the lamellae are also evanescent ; but the tabula; are represented by numerous vesicular plates. The corals of these genera are not always solitary, or merely in groups ; some species of Cyathophyllum constantly form compound masses, with cups rendered polygonal by contact, like C. regium of the Bristol limestone. The allied genus Acervidaria (fig. 4, s) resembles an Astrcea, and exhibits, in a remarkable manner, the multi plication of its corallites by calicular gemination. The genus Lithostrotion (fig. 4, 7) of the carboniferous limestone is also compact and astroeiform, but the new corallites are produced by lateral gemination. Corals, with the same structure, but not compact, are known by the name Lith,odouiron (fig. 4, 6). The "chain-coral" Halysites (fig. 4, and Syringopora (fig. 4, io) resemble, at first sight„ the recent asteroid Tubiporidce : in Halysites the radiating septa are quite rudimentary ; and in Syringopora the tabuLT are funnel-shaped, forming a central axis to each tube. The Fa-r ositidcc (fig. 4, 22) are mostly very regular both as to their polygonal shape and transverse tabulte ; the cells of adjacent corallites are connected by pores, either in the sides or angles of the walls ; the septa are rudimentary. In the genus Chcetetes the tubes are always slender, and much elongated, and their walls imperforate. Michelinia resembles the fruit of the Nelumbium ; it has vesicular tabulaa and root-like processes to its basal plate. Heliolites (fig. 4, 9), of which many species are found in the Silurian and Devonian limestones, is related to the recent ifillepone. The radiating septa are distinct, and the tabuhe regular ; the interspaces between the stars are filled up with fine and regular tubes. One genus of Fungicke (Palceocyclus) occurs in the "Upper Silurian.
Secondary and Tertiary Corals (Anthozoa).
The British secondary corals are not very numerous ; for although specimens abound in the coral-rag districts, only fourteen species are found in that formation. Altogether, sixty-five species are found in the English oolites, and twenty two in the chalk and greensands. These are mostly A strceulce, or related to Fungia. Three common forms in the oolites are Montlivaltia (fig. 5, 9), Stylina (fig. 5, io) and The,cosmilia (fig. 5, :I). The English cretaceous strata afford the Holocystis (fig. 5, 8), which is the most recent coral with quadripartite septa ; Trochocyathus and Parasmilia (fig. 5, 6), resembling the recent Cyathina ; and the little " Fungia" coranula (fig. 5, 3), described in two genera of distinct orders (Micrabacia and Stephanophyllia) in the " Monographs of the Palwonto graphical Society." The lower chalk of France and Germany contains many other corals, especially Cyclolites (fig. 5, s), Pachygyra (fig. 5, 7), and Diploctenium (fig. 5, 2). The Aspi discus (fig. 5, 4) was sent by Dr. Shaw from Algeria.
The English eocene strata contain twenty-five corals, all extinct, and belonging to fifteen genera. These include an A strcea (Litharcca Wcbsteri), which grows on the waterworn flint pebbles ; a Balanophyllia, similar to the existing coral ; a Dendrophyllia, which is the oldest member of the genus ; an Ocutina; and eight species of the genus Turbinolia (fig. 5, 1). The corals of the English pliocene are mostly Bryozoa ; only four true corals have been found in the coralline crag belong ing to the genera Sphenotrochus, Flabellum, Cryptangia, and Balanophyllia, all reputed extinct, although the first is very closely related to the living Spiwnotroch,us Macandreui.
The total number of fossil corals enumerated by M. d'Orbigny in the " Prodrome de Paleontologic," amounts to 1135, grouped under 216 genera. But notwithstanding all the labour which has been bestowed on this branch of paleonto logy by Goldfuss, Michelin, Lonsdale, and Milne Edwards, species are continually discovered or brought home from abroad which are altogether new, and cannot be placed in any of the constituted genera.