OF PREHISTORIC TIMES IN BRITAIN. 263 



different proportions towards the securing of this end, the fact that they do so is of so 

 much the greater morphological value. In Sus cristatus the naso-frontal suture very 

 ordinarily runs, as may be seen in fig. 4 (and in Sus andamanensis, in fig. 3), straight across 

 the roof of the ethmoid, at right angles to the long axis of the skull ; or the frontals may 

 intrude themselves mesially between the nasals, making thus the contour of the suture to 

 be convex forwards. Precisely the reverse is the case in the adult European Wild Boar. 

 Some weight has been laid * upon a similar conformation in the skull of the Tiger, as 

 being of service in differentiating it from the skull of the Lion ; and though it is not 

 pretended that an equally great distinctness can be supposed to exist between the two 

 animals now under comparison, still the structural differences in the two sets of cases 

 are analogous. 



But when we come to look at the skulls of developing Pigs, we see that real value 

 attaches, from this point of view also, to the relatively greater or less extension back- 

 wards of the nasal bones, and the contour described consequently by the naso-frontal 

 suture. A tape crossed at right angles to the long axis of the skull from one infra- 

 orbital foramen to the other, passes very closely in front of, and often parallel with the 

 naso-frontal suture in the very young pig ; the suture gets removed further and further 

 away from it as the pig increases in age. Nathusius (Taf. iii. figs. 11 and 13) has 

 figured the skulls of a young Wild Boar and of an adult Wild Boar upon the same plate ; 

 and the straight line of the suture of the former contrasts most instructively with the 

 backwardly arching contour of the latter. The straightness, therefore, of the naso-frontal 

 suture may be supposed to illustrate the principle that climatic or other conditions may 

 cause structural arrangements to be permanently retained in certain races whilst they 

 are obliterated in others. The retention of the prolongation of tbe sagittal suture over 

 the frontal region is believed, with much reason, to be hereditarily transmitted in our own 

 species ; and I incline to think that the persistence of the frontal tubera with very 

 much of their infantile eminence, which we see not rarely in adult men, may be taken as 

 furnishing another parallel to the retention in some degree, by the adult Sus cristatus, of 

 the characters of the young animal's naso-frontal relations. 



In the fourth place, as regards the value of the relative shortness of the lacrymal 

 bone as a means for differentiating the skulls of Sus cristatus and its allies from 

 those of Sus scrofa, var. ferus, I was for a long time of opinion that the same might 

 be said of this all but invariably observed peculiarity of Sus cristatus, which I have 

 already said, however shortly, of the straightness of its naso-frontal suture; and 

 that all this may, mutatis mutandis, be repeated as to the lacrymal's peculiarities 

 in the two subspecies there can be no doubt. Anybody who will examine the figures 

 given in Spix's ' Cephalogenesis,' or the reproduction of them in Erdl's ' Tafeln der 

 vergleichenden Anatomie des Schadels,' 1841, can convince himself of the fact that 

 the malar border of the lacrymal is very short as compared with its orbital border in the 

 young Pig f ; and if he extend his observation to the various adult Suidse, he will find 



* Ost. Catalog. Royal College of Surgeons of England, 4506. p. 706. 



t Though I do not suppose that it would be possible to say in 1876 what Dr. Gray said (Proc. Zool. Soc. 1868, p. 19) 

 in 1868, to the effect that Nathusius's works were not to be had either in the Library of the British Museum, or in 



