ABSTRACT
As the present short monograph completes my work on British fossil cirripedes, I beg to be permitted again to have the satisfaction of returning my very sincere thanks to the many naturalists who have placed their collections at my disposal, and have given me the freest permission to use the specimens, in whatever manner I might find necessary. My thanks are most especially due to Mr Searles Wood, Mr Bowerbank, and Sir Charles Lyell; and to Mr J . de C. Sowerby for the use of the original specimens figured in the Mineral Conchology. I lie, also, under much obligation to Mr D. Sharpe, Mr Greenough, Mr Smith of Jordan Hill, Professor Tennant, Mr Charlsworth, Mr F. Edwards, Dr T . Wright, Professor Forbes, Professor Henslow, M. Bosquet, and to many others. I must, also, be permitted to tender my grateful thanks to the Council of the Palaeontographical Society for the very liberal manner in which they have allowed my two mono graphs to be illustrated. /
Cirripedia may be divided, as I have recently shown in a monograph on the Balanidae published by the Ray Society,3 into three orders: of these, the Thoracica includes all ordinary cirripedes, and all ever likely to be found fossil, and therefore the two other orders may be here passed over without notice. The Thoracica contains three families: the Balanidae or sessile cirripedes, which in a recent state so abound on the shores of almost every quarter of the world, and which are so frequently found in tertiary deposits; the Verrucidae, which includes only a single genus very singular from its asymmetrical shell; and the Lepadidae, or pedunculated cirripedes; of the latter, the fossil species have been already published by the Palaeontographical Society. The Balanidae and Verrucidae will be treated of in the following pages. As yet only sixteen species in these two families have been found fossil in Great Britain; and of these sixteen, nine are still living forms. As the latter are known only imperfectly in their fossil condition, and as they have lately been described by me in full detail, I have thought it best here only to make a few remarks on such portions of the shells of each species as have hitherto been discovered, adding a few illustrations, such as appeared to me desirable. The extinct species will be fully described: of these, all the figures given are from British specimens. But of the species found both living and fossil, I have in several instances (always so stated) given drawings from recent specimens; some of the valves either not having been found fossil, or found only in an imperfect and not characteristic condition. As so few species in the several genera are known in a fossil condition, I have thought it quite superfluous to give long generic descriptions, which would have required constant references to many species exclusively found living.
