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Show 1867.] MESSRS. BAIRD AND ADAMS ON CHINESE SHELLS. 489 4 inches, is about 2 inches wide, and on the interior surface is provided with about six highly elevated folds, which have other, smaller folds between them. Both begin and end on the entrances of the two pouches at the ends of the stomach. The right pouch, situated near the pylorus, is smaller, but of the same figure and construction as the corresponding one of the other or left side. Over this pouch on the right end a high transverse circular fold separates a small chamber from the central stomach; and this part, after the fold, which is separated into three different lobes by other folds, must be regarded as a separate stomach, or a propylorus, because from it begins the duodenum. There was only a short portion of this intestine ; but I could observe soon after the beginning of it an expansion, like a lateral pouch, which is also known in Phoceena, and very well figured by Bappin his interesting work on the 'Cetacea' (Tubingen, 1837- 38), pl. 6. f. 3f. I find thus a general resemblance in the stomach of Pontoporia to that of Phoceena, if we regard only the fundamental type of both, and not the particular execution of this type in the different genera. In the pouch on the right side of the stomach I found some teeth of a Cephalopodous animal, belonging to the family of Loligo, and also the lenses of the eyes of animals of the same group. This proves that Pontoporia is a marine animal, and that it goes only from curiosity or necessity in stormy times into the mouths of rivers. The individual which we have had for a long time in the Museum was taken near Maldonado, and is also a young animal; but we have skulls of full-grown size, 16" long, which prove that the whole animal may be 4 feet long, the skull being somewhat more in length than the third part of the whole body. My young specimen is 30 inches long, and the skull measures 11 inches. Under these circumstances I cannot believe that the large Dolphin of 1 5 feet in length, seen by Freminville on the coast of Brazil, which Dr. Gray mentions in the * Catalogue of Seals, &c.' p. 232, was of this species. Note.-As I propose to give an extended description of the skeleton and the other parts, illustrated by well-executed figures, in one of the forthcoming numbers of the * Anales del Museo publico de Buenos Aires,' I have not thought it necessary to enter here into any further details respecting their structure. 5. Notes upon some Interesting Chinese Shells, with a Description of T w o or Three N e w Species of Unionidce, collected at Shanghai by Jones Lamprey, M.D., 67th Regiment, C.M.Z.S. By W . BAIRD, M.D., and H. ADAMS, F.L.S. (Plate XXVI.) Amongst a variety of land- and freshwater shells brought from Shanghai by Dr. Lamprey, and lately added to our National Col- |