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Show 312 ON THE FOSSIL VERTEBRATA OF SOUTH AMERICA. [Mai*. 16, able to make brief visits to Rio de Janeiro in Brazil and to Montevideo in Uruguay. In Brazil at present three features of interest claimed attention. The Cretaceous Formations in the provinces of Ceara and Bahia had yielded a large number of remains of marine fishes closely similar to those from deposits of the same age in other parts of the world; and from the neighbourhood of Bahia, within the last few years, Mr. Joseph Mawson had obtained numerous reptilian bones, referable to Mesozoic crocodiles, pterodactyles, plesiosaurs, and probably dinosaurs. Certain lignites occupying isolated basins among the old rocks in the province of Sao Paulo were crowded with the skeletons of Teleostean fishes evidently of a comparatively modern Tertiary period. These were being collected by Dr. von Jhering for the Sao Paulo Museum, and by M r . John Gordon for the British Museum ; and when examined in detail, it seemed likely they would afford much information concerning the immediate ancestors of the existing Brazilian freshwater fish-fauna. A third geological formation of special importance was a series of limestones extensively developed in the province of Sao Paulo, whence Dr. Orville A. Derby some years ago had obtained the remarkable primitive aquatic reptile, Stereosternum tumidum. As originally recognized by Prof. E. D. Cope, who had described this animal, it was extraordinarily similar to Mesosaurus of the Karoo Formation of South Africa-a series of early Mesozoic deposits specially characterized by extinct reptiles which had often been regarded as the possible immediate ancestors of the Mammalia. Dr. Derby had recently found a new specimen of Stereosternum exhibiting almost its complete skeleton, including the remarkably long tail; he had also lately met with an undoubted Labyrinthodont tooth, and there was every indication that before long the important Karoo fauna would be discovered in the South American area. The Uruguayan National Museum in Montevideo contained nothing of much palasontological interest; and the collection of bones of extinct Mammalia from Uruguay, made by Dr. Conrad Moeller, had been presented by that gentleman a few years ago to the University of Christiania, Norway. The National Museum of Argentina at Buenos Aires, under the direction of our Corresponding Member, Dr. Carlos Berg, contained the fine collection of Pleistocene Mammalia described by the late Dr. Burmeister, all well preserved and beautifully mounted. There was also a large collection of late Tertiary fish-remains from the neighbourhood of the city of Parana. The study of these would supplement in an interesting manner the results obtained from the lignite fishes of Sao Paulo. Modern progress, however, in the discovery of the extinct vertebrate fauna of the Argentine Republic was best illustrated not in the National Museum, but in the Buenos Aires State Museum, founded by our Corresponding Member, Dr. F. P. Moreno, at La Plata in 1885. The more important specimens had already been briefly described and well figured in the publications of the Museum |