Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/296

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numerous may have been the ancient species of Annelidans without a shelly covering, naked worms of this class can have left but slight traces of their existence, except the holes they perforated, and the little accumulations of sand or mud cast up at the orifice of these perforations; in a preceding chapter we have noticed examples of this kind. We have also abundant evidence of the early and continued prevalence of that order of Annelidans, which formed shelly calcareous tubes, in the occurrence of fossil Serpulæ in nearly all formations, from the Transition periods to the present time.

history of fossil Crustaceans has been hitherto almost untouched by Palaeontologists, and their relations to the existing Genera of this great Class of the Animal Kingdom are too little known to admit of discussion in this place.