corresponding relations should exist in the vegetable world also. Struck, for instance, by the total absence of sturgeons, perches, pickerels, trouts, carps and other white fishes, cusks, sculpins, &c., I have asked myself, while studying the fishes of the Amazons, what analogy could exist between those of our Western rivers and those of the tropics, as well as between the latter and those of the intermediate latitudes. Looking at them with this view, I have been surprised to find how closely related the Goniodonts are to the Sturgeons; so much so, that the Loricariæ may be considered as genuine Sturgeons, with more extensive shields upon the body. I am satisfied also that the Cychla is a perch to all intents and purposes, that the Acaras are Sunfishes, the Xiphorhamphus (Pirà pucu) Pickerels, and the Curimatas genuine Carps. Now, may not a similar relation exist between the families of plants belonging to the North and those forming the most prominent vegetation of the South? What are the tropical trees which take the place of our elms, maples, lindens? By what families are our oaks, chestnuts, willows, poplars, represented under the burning sun of the equinoctial regions? The Rosaceæ in the temperate and the Myrtaceæ in the tropical regions seem to me such botanical equivalents. The family of Rosaceæ gives to the North its pears, its apples, its peaches, its cherries, its plums, its almonds; in short, all the most delicious fruits of the Old World, as well as its most beautiful flowers. The trees of this family, by their foliage, play a distinguished part in the vegetation of the temperate zone, and impart to it a character of their own. The Myrtaceæ give to the South its guavas, its pitangas, its araçàs, the juicy plum-like fruit of the swamp-myrtles, many of its nuts, and other excellent fruits. This family, including the Melastomaceæ, abounds in flowering shrubs, like the purple Queresma and many others not less beautiful; and some of its representatives, such as the Sapucaia and the Brazilian nut-tree, rise to the height of towering trees. Both of these families sink to insignificance in the one zone, while they assume a dignified port and perform an important part in the other. If this investigation be extended to the shrubs and humbler plants, I believe the botanist who undertakes it will reap a rich harvest.”