Notes on some new Crustaceans from the Lower Eocene of Portsmouth

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Abstract
Having been favoured by Messrs. C.J.A. Meyer and Caleb Evans with the opportunity of examining three new Crustaceans recently obtained by them from the Lower Tertiary Deposits exposed during the excavations for the “Dockyard Extension Works” in Portsmouth Harbour, I beg to submit the following notes thereon. I. Family C orystidæ . (Genus Palæocorystes , Bell.) This family, represented at the present day by the genus Corystes common on our own coast, and in the Chalk, Greensand, and Gault by the genera Palæocorystes and Eucorystes , has now been discovered in the Lower Eocene, at Portsmouth, by Mr. Caleb Evans, F.G.S. The specimen (see Plate IV., figs. 1 a, b), although far from perfect, is sufficient to indicate at once the genus to which it belongs, namely Palæocorystes , and also that it is specifically distinct from those occurring in the Cretaceous rocks, already described by Prof. Bell and others*. The carapace measures one inch in length; but (both its anterior and posterior borders having been injured) it was, originally, probably nearly one-fourth of an inch longer. In breadth it measures 10 lines. Some portion of the anterior (orbital and suborbital) border can still be traced out; but the rostrum is quite destroyed. The surface of the carapace is smooth and devoid of ornamentation, save a few widely scattered and very minute puncta ; but where the delicate cortical layer has been removed, the carapace presents a finely granular structure. The two sigmoid markings, observable on the carapaces of all the Corystidæ are also clearly

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