The best Mollusks for this purpose are the Limnaea, the Planorbis, the Physa, the Vivipara and some of the “pigmies” just mentioned. Much can be learned concerning the habits of our common snails if a record is kept of everything the animal does, such as its mode of eating, what it will eat and the increase in size from day to day of the little snails after they are hatched from the egg. If these creatures could be considered by the majority of people as living, breathing animals, performing many of the functions carried on by our own bodies they would be regarded with more favor and hence aquaria would become more numerous and they would also be studied more intelligently. The writer has been frequently amused (and sometimes pained) by the careless question of some otherwise intelligent person, when he has been exhibiting the shell of some interesting mollusk, “Well, really, now, was that thing ever alive?” It is to be earnestly hoped that this series of articles will reach many of this class of people and lead them to a better understanding of these lowly creatures. Frank Collins Baker. THE ORANGE. (_Citrus aurantium._) The tree which produces the well-known Orange of commerce is closely related to the lemon, the citron and the lime, and with them belongs to the genus Citrus. By some it is supposed that Linnaeus selected this name, deriving it from a corruption of the Greek word meaning cedar-tree, because, like the cedar, it is an evergreen. By others it is held that the name was chosen in honor of the city of Citron in Judea. In ordinary language the name citron is applied to another species of the genus, the fruit of which is oblong, about six inches in length and with a thick rind. Many consider that the name Orange is a direct corruption of the Latin word aureum, meaning golden; but our best authorities on the derivation of words believe that the name, though a corruption, reached its present form in the following manner: “The Sanskrit designation nagrungo, becoming narungle in Hindustani, and corrupted by the Arabs into naranj (Spanish naranja), passed by easy transitions into the Italian arancia (Latinized aurantium), the Roman arangi, and the later Provincial Orange.”