to which man belongs, occasionally make their appearance in him, though not found in the normal human embryo; or, if normally present in the human embryo, they become abnormally developed, although in a manner which is normal in the lower members of the group. These remarks will be rendered clearer by the following illustrations.

In various mammals the uterus graduates from a doublo crgan, with two distinct orifices and two passages, as in the marsupials, into a single organ, which is in no way double, except from having a slight internal fold, as in the higher apes and man. The rodents exhibit a perfect series of gradations between these two extreme states. In all mammals the uterus is developed from two simple primitive tubes, the inferior portions of which form the cornua; and it is, in the words of Dr. Farre," by the coalescence of the two cornua at their lower extremities that the body of the uterus is formed in man; "while in those animals in which no middle portion of body exists, the cornua remain un-united. As the development of "the uterus proceeds, the two cornua become gradually shorter, "until at length they are lost, or, as it were, absorbed into the "body of the uterus." The angles of the uterus are still produced into cornua, even in animals as high up in the scale as the lower apes and lemurs.

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Now in women, anomalous cases are not very infrequent, in which the mature uterus is furnished with cornua, or is partially divided into two organs; and such cases, according to Owen, repeat "the grade of concentrative development," attained by certain rodents. Here perhaps we have an instance of a simple arrest of embryonic development, with subsequent growth and perfect functional development; for either side of the partially double uterus is capable of performing the proper office of gestation. In other and rarer cases, two distinct uterine cavities are formed, each having its proper orifice and passage." No such stage is passed through during the ordinary development of the embryo, and it is difficult to believe, though perhaps not impossible, that the two simple, minute, primitive tubes should know how (if such an expression may be used) to grow into twe

there is any relation between the development of supernumerary digits and reversion to some lowly organised progenitor of man.

39 See Dr. A. Farre's well-known Article in the 'Cyclopædia of

Anatomy and Physiology,' vol v.. 1859, p. 642. Owen, Anatomy of Vertebrates,' vol. iii., 1868, p. 687. Professor Turner in 'Edin burgh Medical Journal,' February, 1865.

distinct uteri, each with a well-constructed orifice and passage, and each furnished with numerous muscles, nerves, glands and vessels, if they had not formerly passed through a similar course of development, as in the case of existing marsupials. No one will pretend that so perfect a structure as the abnormal double uterus in woman could be the result of mere chance. But the principle of reversion, by which a long-lost structure is called back into existence, might serve as the guide for its full development, even after the lapse of an enormous interval of time.

40

Professor Canestrini, after discussing the foregoing and various analogous cases, arrives at the same conclusion as that just given. He adduces another instance, in the case of the malar bone,1o which, in some of the Quadrumana and other mammals, normally consists of two portions. This is its condition in the human foetus when two months old; and through arrested development, it sometimes remains thus in man when adult, more especially in the lower prognathous races. Hence Canestrini concludes that some ancient progenitor of man must have had this bone normally divided into two portions, which afterwards necame fused together. In man the frontal bone consists of a single piece, but in the embryo, and in children, and in almost all the lower mammals, it consists of two pieces separated by a distinct suture. This suture occasionally persists more or less distinctly in man after maturity; and more frequently in ancient than in recent crania, especially, as Canestrini has observed, in those exhumed from the Drift, and belonging to the brachycephalic type. Here again he comes to the same conclusion as in the analogous case of the malar bones. In this, and other instances presently to be given, the cause of ancient races approaching the lower animals in certain characters more frequently than do the modern races, appears to be, that the latter stand at a somewhat

40 Annuario della Soc. dei Naturalisti in Modena,' 1867, p. 83. Prof. Canestrini gives extracts on this subject from various authorities. Laurillard remarks, that as he has found a complete similarity in the form, proportions, and connection of the two malar bones in several human subjects and in certain apes, he cannot consider this disposition of the parts as simply accidental. Another paper on this same anomaly has been published by Dr. Saviotti in the Gazzetta delle Cliniche,' Turin, 1871, where he says that traces of the division may be de

tected in about two per cent. of adult skul; he also remarks that it more frequently occurs in prognathous skulls, not of the Aryan race, than in others. See also G. Delorenzi on the same subject; 'Tre nuovi casi d'anomalia dell'osso, malare,' Torino, 1872. Also. E. Morselli, Sopra una rara anomalia dell'osso malare,' Modena, 1872. Still more recently Gruber has written a pamphlet on the division of this bone. give these references because a reviewer, without any grounds or scruples, has thrown doubts on my statements.

greater distance in the long line of descent from their early semihuman progenitors.

Various other anomalies in man, more or less analogous to the foregoing, have been advanced by different authors, as cases of reversion; but these seem not a little doubtful, for we have to descend extremely low in the mammalian series, before we find such structures normally present.11

In man, the canine teeth are perfectly efficient instruments for mastication. But their true canine character, as Owen12 remarks, “is indicated by the conical form of the crown, which "terminates in an obtuse point, is convex outward and flat or "sub-concave within, at the base of which surface there is a feeble prominence. The conical form is best expressed in the "Melanian races, especially the Australian. The canine is more deeply implanted, and by a stronger fang than the incisors." Nevertheless, this tooth no longer serves man as a special weapon for tearing his enemies or prey; it may, therefore, as far as its proper function is concerned, be considered as rudimentary. In. every large collection of human skulls some may be found, as Häckel 43 observes, with the canine teeth projecting considerably beyond the others in the same manner as in the anthropomorphous apes, but in a less degree. In these cases, open spaces between the teeth in the one jaw are left for the reception of the canines of the opposite jaw. An interspace of this kind in a Kaffir skull, figured by Wagner, is surprisingly wide. Considering how few are the ancient skulls which have been examined, compared to recent skulls, it is an interesting fact that in at least three cases the canines project largely; and in the Naulette jaw they are spoken of as enormous.45

41 A whole series of cases is given by Isid. Geoffroy St.-Hilaire, Hist. des Anomalies,' tom. iii. p. 437. A reviewer (Journal of Anat. and Physiology, 1871, p. 366) blames me much for not having discussed the numerous cases, which have been recorded, of various parts arrested in their development. He sys that, according to my theory, 66 every transient condition of an organ, during its development, is "not only a means to an end, but 66 once was an end in itself." This does not seem to me necessarily to hold good. Why should not variations occur during an early period of development, having no relation to reversion; yet such variations might be preserved and accumulated.

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Of the anthropomorphous apes the males alone have their canines fully developed; but in the female gorilla, and in a less degree in the female orang, these teeth project considerably beyond the others; therefore the fact, of which I have been assured, that women sometimes have considerably projecting canines, is no serious objection to the belief that their occasiona! great development in man is a case of reversion to an ape-like progenitor. He who rejects with scorn the belief that the shape of his own canines, and their occasional great development in other men, are due to our early forefathers having been provided with these formidable weapons, will probably reveal, by sneering, the line of his descent. For though he no longer intends, nor has the power, to use these teeth as weapons, he will unconsciously retract his "snarling muscles" (thus named by Sir C. Bell), so as to expose them ready for action, like a dog prepared to fight.

46

Many muscles are occasionally developed in man, which are proper to the Quadrumana or other mammals. Professor Vlacovich examined forty male subjects, and found a muscle, called by him the ischio-pubic, in nineteen of them; in three others there was a ligament which represented this muscle; and in the remaining eighteen no trace of it. In only two out of thirty female subjects was this muscle developed on both sides, but in three others the rudimentary ligament was present. Thi muscle, therefore, appears to be much more common in the male than in the female sex; and on the belief in the descent of man from some lower form, the fact is intelligible; for it has been detected in several of the lower animals, and in all of these it serves exclusively to aid the male in the act of reproduction.

Mr. J. Wood, in his valuable series of papers,48 has minutely described a vast number of muscular variations in man, which resemble normal structures in the lower animals. The muscles

pp. 241, 242; vol. xv. 1867, p. 544; vol. xvi. 1868, p. 524. I may here add that Dr. Murie and Mr. St. George Mivart have shewn in their Memoir on the Lemuroidea (‘Tran act. Zoolog. Soc.' vol. vii. 1869, p. 96), how extraordinarily variable some of the muscles are in these animals, the lowest members of the Primates. Gradations, also, in the muscles leading to structures found in animals still lower in the scale, are numerous in the Lemuroidea

49

which closely resemble those regularly present in our nearest allies, the Quadrumana, are too numerous to be here even specified. In a single male subject, having a strong bodily frame, and well-formed skull, no less than seven muscular variations were observed, all of which plainly represented muscles proper to various kinds of apes. This man, for instance, had on both sides of his neck a true and powerful "levator claviculæ,” such as is found in all kinds of apes, and which is said to occur in about one out of sixty human subjects. Again, this man had " a special abductor of the metatarsal bone of the fifth digit, such as Professor Huxley and Mr. Flower have shewn " to exist uniformly in the higher and lower apes." I will give only two additional cases; the acromio-basilur muscle is found in all mammals below man, and seems to be correlated with a quadrupedal gait,50 and it occurs in about one out of sixty human subjects. In the lower extremities Mr. Bradley 51 found an abductor ossis metatarsi quinti in both feet of man; this muscle had not up to that time been recorded in mankind, but is always present in the anthropomorphous apes. The muscles of the hands and arms-parts which are so eminently characteristic of man-are extremely liable to vary, so as to resemble the corresponding muscles in the lower animals.5 Such resemblances are either perfect or imperfect; yet in the latter case they are manifestly of a transitional nature. Certain variations are more common in man, and others in woman, without our being able to assign any reason. Mr. Wood, after describing numerous variations, makes the following pregnant remark: “Notable departures from the ordinary type of the muscular “structures run in grooves or directions, which must be taken "to indicate some unknown factor, of much importance to a comprehensive knowledge of general and scientific anatomy."

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49 See also Prof. Macalister in 'Proc. R. Irish Academy,' vol. x. 1868, p. 124.

50 Mr. Champneys in 'Journal of Anat. and Phys.' Nov., 1871, p. 178.

51 Journal of Anat. and Phys.' May, 1872, p. 421.

52 Prof. Macalister (ibid. p. 121) has tabulated his observations, and finds that muscular abnormalities are most frequent in the fore-arms, secondly, in the face, thirdly, in the foot, &c.

53 The Rev. Dr. Haughton, after giving (Proc. R. Irish Academy,' June 27, 1864, p. 715) a remark

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able case of variation in the human flexor pollicis longus, adds, "This "remarkable example shews that "man may sometimes possess the "arrangement of tendons of thumb "and fingers characteristic of the macaque; but whether such a 66 case should be regarded as a macaque passing upwards into a man, or a man passing downwards "into a macaque, or as a congenital "freak of nature, I cannot under"take to say." It is satisfactory to hear so capable an anatomist, and so embittered an opponent of evolutionism, admitting even the

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