peculiarities, and in which particular attention is paid to the perforation or non-perforation of the beak; Trilobos being distinguished as “_vertice integro_,” Bursula as _Terebratulæformes_ rostro non perforato, &c. And we may lastly mention that from some original MSS. of Da Costa, in our possession, it appears that Anomia was a general term for the whole family, and _Terebratula Anomiæ lævis_ was the term by which the English and other Naturalists, long prior to the middle of last century, were accustomed to distinguish the same kind of shells which in the modern nomenclature of Conchology is also named generically Terebratula. Da Costa, as Librarian of the Royal Society, was in the habit of correspondence with the learned men of his time throughout Europe, and his local knowledge from this circumstance, though never committed to the press, is not likely to be disputed. We could proceed yet further, but enough has surely been advanced to shew that so far from Linnæus having confounded the Terebratula with the Anomia, he left them precisely as he found them, placing them after the example of his predecessors, under the comprehensive term of Anomia, which they had assigned to them. And we have also said enough to prove that to ascribe the Genus Terebratula to either Bruguière or Lamarck can result only from our ignorance of that information which in former days was regarded as the best criterion of an able Naturalist, a correct knowledge of the labours of his predecessors. Under all its circumstances it may be a matter of some indifference to the scientific Naturalist whether in the arrangement of the Anomiæ we follow the concise method of the old writers and Linnæus among the number, or the diffuse distribution of later writers. If we place them in different families according to their characters, whether regarded as sectional distinctions of Anomia, or as distinct genera, we shall at least produce some consistency in the arrangement. But there is yet another mode of arrangement which appears to be the favourite theme with some Conchologists of the present day, and which it may be proper in this place to mention, namely, the classification of shells according to their animals. This has been attempted in the work of Cuvier, his “Règne Animal,” and the result of this endeavour, so far as it relates to the Anomia in particular, may in this place deserve our explicit observation. In this work (_Règne Animal_) Cuvier endeavouring to class the Anomiæ according to the animals known to inhabit them, as well as those which he imagines for the fossil tribes, so disperses them, that the Trochi, Turbines, Nautili, Volutæ, and indeed nearly the whole of the _Univalves_ intervene between his two first genera of these _bivalves_, Hyalæa and Anomia; and the Anomia tridentata of Forskahl, which is the Hyalæa of this author, is placed with Clio (the shell of which is our _Bulla Aperta_[26]) among the _Ptéropodes_. After the long