THE ANNALS AND MAGAZINE OF NATURAL HISTORY, [THIRD SERIES.] No. 4. APRIL 1858. XXI. — Notes on the Palceozoic Bivalved Entomostraca. No. IV. Some North American Species. By T. Rupert Jones, F.G.S. [With two Plates.] [Continued from 2nd Series, vol. xvii. p. 101.] The Entomostraca which I propose to describe in this communi-cation have been brought from different parts of North America at different times, and kindly submitted to me for examination. The series of specimens from Canada were placed in my hands, in 1851, by Sir W. E. Logan; and I intended to describe them at once, but found that, without a more definite knowledge of the Beyrichice and allied forms already noticed by geologists, I could not do justice to the work. The Notes I., XL, & III., on Palaeozoic Bivalved Entomostraca, published in former volumes of the ^ Annals,^ have been the result of my inquiries on this subject ; and at last I felt more capable of handling the series set before me. In the meantime, other North American mate-rials came to hand. A portion of these specimens have taken their place as illustrative of generic characters in the former papers ; and a portion remain to be noticed here, including the smaller Entomostraca in the limestone of Beechey Island, a few specimens from the United States in the Geological Society^s Museum, and, more especially, a valuable series of beautiful specimens from Pennsylvania, which Prof. H. D. Rogers has most considerately and kindly permitted me to describe as illus-trative fossils of the Geological Survey of that State. Several species of bivalved Entomostraca have been already Ann. S^^ Mag. N. Hist. Ser. 3. Vol.'u 16
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