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Show UMMA.RY OF THE CONTENTS. 457 On the dogs of outh America i both the aboriginal race and the descendant of European dogs which have become wild. Sufferings of cats when taken to elevations exceeding 131000 (131850 Eng.) feet . . . . . . . . . . . 98-102 The low tract of the ahara, and its relations to the Atlas Mountains, according to the latest information given by Daumas, Carette, and Renou. The barometric measurements of Fournel make it appear very probable that part of the North African desert is lower than the level of the e~. Oasis of Biscara; abundance of fossil salt in zones or bands runmng from south-west to north-east. Causes of the nocturnal cold in the desert according to Melloni . 102- 106 Notices of the River Wady-Dra (1-6th longer than the Rhine, and dry a large portion of the year), and of the country of Sheikh Beirouk, a chief independent of the Emperor of Morocco, from manuscript communications of the Naval Captain Count Bouet-Villaumez. The mountains north of Cape Noun (a name used by Edresi, in which, since the 15th century, an allusion to the negative particle has been erroneously sought) attain 8600 (9166 English) feet of elevation 106- 107 The vegetation of the tropical American Llanos consisting of grasses, compared with the vegetation of the North Asiatic Steppes consisting of herbaceous plants.· In the last-named Steppes, and especially the more fertile among them, a pleasing effect is produced in spring by small snow-white and red-flowering Rosacere, Amygdalere, species of Astragalus, Crown Imperials, Cypripedias, and Tulips. Contrast with the desolate salt Steppes full of Chenopodiacere, species of Salsola and Atriplex. Considerations on the relative numbers of the prevailing families of plants. The plains adjoining the Icy Sea, north of the limit determined by Admiral Wrangel as that of the growth of Coniferre and Amentacere, are the domain of cryptogamous plants. Aspect and physiognomy of the Tundras, where the soil, which is perpetually frozen, is covered either with a thick coating of Sphagnum and other mosses, or with the snow-white Cenomyce and Stereocaulon paschale . . . . . . 107-109 Principal causes of the very different distribution of temperature in the European and American Continents. Direction and curvature of the isothermal lines, or lines of equal temperature, for the entire year, for the winter, and for the summer . . . . . 109- 119 Are there any grounds for believing that America emerged later than the Old Continent from the chaotic watery covering~ . . 119-121 Thermic comparison of the Northern and Southern Hemispheres in high latitudes . . . . . . . . . . 121-123 Apparent connection of the African sea of sand with those of Persia, Kerman, Beloochistan, and the interior of Asia. On the western part 39 |