Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/290

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Mr. Parkinson on Hippurites.

satisfaisante.” (Description de plusieurs nouvelles espéces d'orthocératites, &c. p. 15.)

A due attention however to their peculiar organization would, it may be supposed, have prevented the multilocular shells from having been considered as pelagian shells. But M. Denys de Montfort, with most of the French oryctologists, is disposed to believe that all those shells which are known to us only in a fossil state, and which have therefore been supposed to belong to animals which are now extinct, do actually belong to animals which constantly inhabit the bottom of the sea, never rising to the surface, or appearing on the shores. Thus the orthoceratites, ammonites, and belemnites, notwithstanding their possessing different modifications of that organisation by which the nautilus is enabled to raise itself to the surface of the water, are all considered as petrified pelagian shells, whose recent analogues have not yet been brought to view. Thus speaking of the simplégade couleuvrée (simplagades colubratus), a fossil shell hitherto considered as an ammonite, but which this author has thought right to place under a distinct genus, he says, “ Il est très probable que les simplégades, comme beaucoup d'autres mollusques pélagiens, vivent dans le fond des hauts mers, et qu'une cause physique quelconque ne leur permet point de paroitre à la surface des eaux.” (Conchologie Systematique, &c. p. 84.)

Having already opposed this opinion in a general way, in my Examination of the organic remains of a former world; and having shown that in all the known multilocular fossil shells such an organization existed as was well calculated to enable the animals to raise themselves occasionally to the surface of the water, I shall here endeavour to determine how far the specimens presented to the Society will show, that this property was possessed by the hippurites.

On examining those parts of this fossil, which have been hitherto