The aspect of the question as to the origin of the melon has completely changed since the experiments of Naudin. The paper which he published in 1859, in the _Annales des Sciences Naturelles_, 4th series, vol. ii., on the genus _Cucumis_, is as remarkable as that on the genus _Cucurbita_. He gives an account of the observations and experiments of several years on the variability of forms and the crossed fecundation of a multitude of species, breeds, or varieties coming from all parts of the world. I have already spoken (p. 250) of the physiological principle on which he believes it possible to distinguish those groups of forms which he terms species, although certain exceptions have occurred which render the criterion of fertilization less absolute. In spite of these exceptional cases, it is evident that if nearly allied forms can be easily crossed and produce fertile individuals, as we see, for example, in the human species, they must be considered as constituting a single species. In this sense _Cucumis Melo_, according to the experiments and observations made by Naudin upon about two thousand living plants, constitutes a species which comprehends an extraordinary number of varieties and even of breeds; that is to say, forms which are preserved by heredity. These varieties or races can be fertilized by each other, and yield varied and variable products. They are classed by the author into ten groups, which he calls _canteloups_, _melons brodés_, _sucrins_, _melons d’hiver_, _serpents_, _forme de concombre_, _Chito_, _Dudaim_, _rouges de Perse_, and _sauvages_, each containing varieties or nearly allied races. These have been named in twenty-five or thirty different ways by botanists, who, without noticing transitions of form, the faculty of crossing or of change under cultivation, have distinguished as species all the varieties which occur in a given time or place. Hence it results that several forms found wild, and which have been described as species, must be the types and sources of the cultivated forms; and Naudin makes the very just observation that these wild forms, which differ more or less the one from the other, may have produced different cultivated varieties. This is the more probable that they sometimes inhabit countries remote from each other as Southern Asia and tropical Africa, so that differences in climate and isolation may have created and consolidated varieties.