Origin of Species Variorum

With species in a state of nature, every naturalist has in fact brought descent into his classification; for he includes in his lowest grade, or that of a species, the two sexes; and how enormously these sometimes differ in the most important characters, is known to every naturalist: scarcely a single fact can be predicated in common of the adult males and hermaphrodites of certain cirripedes, .. and yet no one dreams of separating them. As soon as the three Orchidean forms, Mona-chanthus, Myanthus, and Catasetum, which had previously been ranked as three distinct genera, were known to be sometimes produced on the same plant, they were immediately considered as varieties; but now I have been able to show that they really constitute the male, female, and hermaphrodite forms of the same species. The naturalist includes as one species the several larval stages of the same individual, however much they may differ from each other and from the adult; as he likewise does the so-called alternate generations of Steenstrup, which can only in a technical sense be considered as the same individual. He includes monsters and varieties, not because they may closely resemble the parent-form, but because they are descended from it. ↑ ↑

As descent has universally been used in classing together the individuals of the same species, though the males and females and larvæ are sometimes extremely different; and as it has been used in classing varieties which have undergone a certain, and sometimes a considerable amount of modification, may not this same element of descent have been unconsciously used in grouping species under genera, and genera under higher groups, though in these cases the modification has been much greater in degree, and has taken a longer time to complete? I believe it has thus been unconsciously