_The Birds of Siberia_.--In an important treatise, published under the patronage of the Imperial Geographical Society of St. Petersburg, and which is the second of a series intended to be issued on Siberian zoology, the author, Herr Radde, not only records the species, but gives an account of the period of the migration of Siberian birds. He {139} gives a list of 368 species, which he refers to the following orders: Rapaces, 36; Scansores, 19; Oscines, 140; Gallinaceae, 18; Grallatores, 74; and Natatores, 81. Concerning the migration of birds, Herr Radde confirms the result arrived at by Von Middendorf in his learned memoir, "Die Isepiptesen Russlands;" the most important of them being, (1) that the high table-land of Asia and the bordering ranges of the Altai, Sajan, and Dauria retard the arrival of the migratory birds; (2) eastward of the upper Lena, toward the east coast of Siberia, a considerable retardation of migrants is again noticeable; and (8) the times of arrival at the northern edge of the Mongolian high steppes are altogether earlier than those of the same species on the Amoor. _Plants within Plants_.--In one of the recent numbers of the "Comptes Rendus," N. Trécul gives an account of some curious observations, showing that plants sometimes are formed within the cells of existing ones. He considers that the organic matter of certain vegetable cells can, when undergoing putrefaction, transform itself into new species, which differ entirely from the species in which they are produced. In the bark of the elder, and in plants of the potato and stone-crop order, he found vesicles full of small tetrahedral bodies containing starchy matter, and he has seen them gradually transformed into minute plants by the elongation of one of their angles.