I was just amused because I found a quote from someone who was arguing basically the same thing, and using the idea to rank the different races.
The probability may now be assumed that the human race sprung from one stock, which was at first in a state of simplicity, if not barbarism. As yet we have not seen very distinctly how the various branches of the family, as they parted off, and took up separate ground, became marked by external features so peculiar. Why are the Africans black, and generally marked by coarse features and ungainly forms? Why are the Mongolians generally yellow, the Americans red, the Caucasians white? Why the flat features of the Chinese, the small stature of the Laps, the soft round forms of the English, the lank features of their descendants, the Americans? All of these phenomena appear, in a word, to be explicable on the ground of development. We have already seen that various leading animal forms represent stages in the embryotic progress of the highest--the human being. Our brain goes through the various stages of a fish's, a reptile's, and a mammifer's brain, and finally becomes human. There is more than this, for, after completing the animal transformations, it passes through the characters in which it appears, in the Negro, Malay, American, and Mongolian nations, and finally is Caucasian. The face partakes of these alterations. "One of the earliest points in which ossification commences is the lower jaw. This bone is consequently sooner completed than the other bones of the head, and acquires a predominance, which, as is well known, it never loses in the Negro. During the soft pliant state of the bones of the skull, the oblong form which they naturally assume, approaches nearly the permanent shape of the Americans. At birth, the flattened face, and broad smooth forehead of the infant, the position of the eyes rather towards the side of the head, and the widened space between, represent the Mongolian form; while it is only as the child advances to maturity, that the oval face, the arched forehead, and the marked features of the true Caucasian, become perfectly developed."* The leading characters, in short, of the various races of mankind are simply representations of particular stages in the development of the highest or Caucasian type. The Negro exhibits permanently the imperfect brain, projecting lower jaw, and slender bent limbs of a Caucasian child some considerable time before the period of its birth. The aboriginal American represents the same child nearer birth. The Mongolian is an arrested infant newly born. And so forth. All this is as respects form; but whence colour? This might be supposed to have depended on climatal agencies only; but it has been shewn by overpowering evidence to be independent of these. In further considering the matter, we are met by the very remarkable fact that colour is deepest in the least perfectly developed type, next in the Malay, next in the American, next in the Mongolian, the very order in which the degrees of development are ranged. May not colour, then, depend upon development also? We do not, indeed, see that a Caucasian fetus at the stage which the African represents is anything like black; neither is a Caucasian child yellow, like the Mongolian. There may, nevertheless, be a character of skin at a certain stage of development which is predisposed to a particular colour when it is presented as the envelope of a mature being. Development being arrested at so immature a stage in the case of the Negro, the skin may take on the colour as an unavoidable consequence of its imperfect organization. It is favourable to this view, that Negro infants are not deeply black at first, but only acquire the full colour tint after exposure for some time to the atmosphere. Another consideration in its favour is that there is a likelihood of peculiarities of form and colour, since they are so coincident, depending on one set of phenomena. If it be admitted as true, there can be no difficulty in accounting for all the varieties of mankind. They are simply the result of so many advances and retrogressions in the developing power of the human mothers, these advances and retrogressions being, as we have formerly seen, the immediate effect of external conditions in nutrition, hardship, &c., and also, perhaps, to some extent, of the suitableness and unsuitableness of marriages, for it is found that parents too nearly related tend to produce offspring of the Mongolian type,--that is, persons who in maturity still are a kind of children. According to this view, the greater part of the human race must be considered as having lapsed or declined from the original type. In the Caucasian or Indo-European family alone has the primitive organization been improved upon. The Mongolian, Malay, American, and Negro, comprehending perhaps five-sixths of mankind, are degenerate. Strange that the great plan should admit of failures and aberrations of such portentuous magnitude! But pause and reflect; take time into consideration: the past history of mankind may be, to what is to come, but as a day. Look at the progress even now making over the barbaric parts of the earth by the best examples of the Caucasian type, promising not only to fill up the waste places, but to supersede the imperfect nations already existing. Who can tell what progress may be made, even in a single century, towards reversing the proportions of the perfect and imperfect types? and who can tell but that the time during which the mean types have lasted, long as it appears, may yet be thrown entirely into the shade by the time during which the best types will remain predominant?
--Robert Chambers, Vestiges of the Natural History of Mankind, 1844.
To wit: whites are the most advanced, perfect race, and so they progress in the womb from Negro to Malay to Indian forms, being born sort of Mongoloid, until finally they grow up to be white.
Of course, it's probably unfair to describe this as similar to Haeckel's idea, since Haeckel published thirty years after Vestiges' first edition.