The only Sicilian species is Conotrochus typus, Seg., a most variable form. M. Seguenza sent me a collection of specimens of the species, and there has been no difficulty in determining the specific identity of the Australian and Sicilian forms. The second, Australian species, Conotrochus M'Coyi, differs from Conotrochus typus in the stoutness of its epitheca, in its form, and in its small calice and columella. The genus is not represented in the recent coral faunas or in any strata except the Sicilian marl and the Australian Cainozoic.
The four species of the genus Flabellum found in the Australian tertiary deposits are very remarkable. Two of them are peculiar to the strata, and the others are well-known in the faunas of the Red Sea and the China and Japan seas. The genus is large, and numbers about fifty species, which are divided into those with a very small pedicel, those with a large base which was once attached (truncate), those always adherent by a large base, and those having root-like processes of epitheca.
The species hitherto recognized in the fossil condition belong to the first division ; but in the Australian Tertiaries two of the truncate forms are found.
The recent species are found especially in the great Coral ocean between the east coast of Africa and the west coast of America. Many are found in the Red Sea, and in the Chinese and Japanese seas ; and one exists off the coast of New Zealand. None have been found in the West-Indian seas ; but a degenerate form lives in the North Sea, the Bay of Biscay, and probably in the Mediterranean. The truncate division contains many species ; and those whose localities are known range from China, the Philippines, and Indian Ocean to the Australian coast near Hardy Island. The division with a small pedicel had a species in the Lower Chalk, many in the Eocene of Europe and America, and a considerable number in the Miocene and Pliocene deposits of Europe. The species found in the Miocene of the West Indies were two in number only.
Flabellum distinctum, which is found in two of the beds near Cape Otway, is a well-known form in the Red Sea and off the coast of Japan. With Flabellum pavoninum, Lesson, of Singapore and China, F. extensum, Michel., found in the European Miocene and, probably, Oligocene strata, F. intermedium, Edw. & H., from the Miocene of Tortona, and F. Basteroti, Edw. & H., of the Faluns, the Flabellum distinctum forms a series of very indistinctly separable species. They are all probably varieties of an early type, and are not worthy of the title of separate species. Finding the so-called species F. distinctum in the Cainozoic of Australia, and in the sea to the northeast, does not interfere with the belief that all the forms just mentioned have lasted, interrupted only by slight variation, from the Oligocene up to the present time.
Flabellum gambierense is a pedicellate form. During its youth it has no spines, and is almost claviform ; but with age it grows tall and curved, and throws forth curiously twisted processes of epitheca. It is not like any other Flabellum. Flabellum Candeanum and F. Victorioe are the fossil truncate species. The first is found in the
