38 THE DESCENT OF MAN. 



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 nor- 

 mally divided into two portions, which afterwards became 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 mam- 

 mals, 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 greater distance 

 in the long line of descent from their early semi-human progeni- 

 tors. 



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.*' 



of the parts as simply accidental. Another paper on this same anomaly 

 has been published by Dr. Saviotti in the 'Gazetta delle Cliniche' Turin, 

 1871, where he says that traces of the division may be detected in about 

 two per cent, of adult skulls; he f.lso 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 

 deir 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. I give these 

 references because a. reviewer, without any grounds or scruples, has 

 thrown doubts on my statements. 



*iA 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 says that, according to my theory, "every tran- 

 "sient condition of an organ, during its development, is not only a 

 "means to an end, but 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, if in any way ser- 

 viceable, for instance, in shortening and simplifying the course of de- 



