feet--a height at which the barometer sank to 13 inches 11-1/5 lines (14.850 English inches), we saw winged insects fluttering around us. We could see that they were Dipteras, resembling flies, but on a sharp ridge of rock (cuchilla) often only ten inches wide, between steeply descending masses of snow, it was impossible to catch the insects. The height at which we saw them was nearly the same at which the uncovered trachytic rock, piercing through the eternal snows, gave to our view, in Lecidea geographica, the last traces of vegetation. The insects were flying at a height of about 2850 toises (18225 E. feet), or about 2600 E. feet higher than Mont Blanc. Somewhat lower down, at about 2600 toises (10626 E. feet), also therefore within the region of perpetual snow, Bonpland had seen yellow butterflies flying very near the ground. According to our present knowledge the Mammalia which live nearest to the region of perpetual snow are in the Swiss Alps, the Marmot which sleeps through the winter, and a very small field-mouse (Hypudæus nivalis), described by Martins, which on the Faulhorn lays up a store of the roots of phænogamous alpine plants almost under the snow. (Actes de la Société Helvétique, 1843, p. 324.) The beautiful Chinchilla, of which the bright and silky fur is so much prized, is often supposed by Europeans to be an inhabitant of the high mountain regions of Chili: this, however, is an error; the Chinchilla laniger (Gray) only lives in the mild temperature of the lower zone, and is not found farther south than the parallel of 35°. (Claudio Gay, Historia fisica y politica de Chile, Zoologia, 1844, p. 91.) While on our European Alps, Lecideas, Parmelias, and Umbilicarias form only a few coloured patches on the rocks which are not completely covered with snow, in the Andes, beautiful flowering phænogamous plants, first described by us, live at elevations of thirteen to fourteen thousand feet (13700 to nearly 15000 E.) We found there woolly species of Culcitium and Espeletia (C. nivale, C. rufescens, and C. reflexum, E. grandiflora, and E. argentea), Sida pichinchensis, Ranunculus nubigenus, R. Gusmanni with red or orange-coloured blossoms, the small moss-like umbelliferous plant Myrrhis andicola, and Fragosa arctioides. On the declivity of the Chimborazo the Saxifraga boussingaulti, described by Adolph Brongniart, grows beyond the limit of perpetual snow on loose boulders of rock, at 14796 (15770 E.) feet above the level of the sea, not at 17000, as stated in two estimable English journals. (Compare my Asie Centrale, T. iii. p. 262, with Hooker, Journal of Botany, vol. i. 1834, p. 327, and Edinburgh New Philosophical Journal, vol. xvii. 1834, p. 380.) The Saxifrage discovered by Boussingault is certainly, up to the present time, the highest known phænogamous plant on the surface of the earth.