260 PROF. ROLLESTON ON THE DOMESTIC PIG 



which, together with two others, with the same appearance as to textural condition, 

 had been brought out of the stores of the Museum into its series. Both these other 

 skulls possessed the short lacrymal so characteristic, as the subjoined tables of measure- 

 ments will show, of Sus cristatus and its allies, together with the other points usually 

 observed in that animal's skull. The principal points, besides those of general fades 

 and proportions, which appeared to me to justify this assignment of skull 3251 a (Royal 

 College of Surgeons) were, in the absence of the shortness of the lacrymal: — first, the 

 great prominence of what may be called the lacrymo-frontal ridge, that part of the 

 frontal bone, to wit, which lies between the channel for the supraorbital nerve mesially 

 and the upper border of the lacrymal bone outwardly ; secondly, the great relative deve- 

 lopment of the part of the third molar which is posterior to the two anterior bicus- 

 pidate lobes of that tooth ; thirdly, the absence of convexity backwards in the naso- 

 frontal suture. These three points are usually present in Sus cristatus, as seen in 

 figures 4 and 6, appended to this paper, and taken from two Indian specimens ; and they 

 are usually found to be accompanied by the fourth peculiarity of a short lacrymal. One 

 or other of these characters may be absent ; but in an undoubted specimen of an adult 

 male Sus cristatus I have never seen more than one of these missing; whilst it is rare 

 for the second, and very rare for either the first or the third, to be found in undoubted 

 specimens of the Pakearctic Wild Boar. In a skull figured by Mr. Bichardson (I. c. p. 50), 

 from " an excavation in an island on Loch Gur, a lake in the neighbourhood of Limerick," 

 and " found in company with skulls of oxen, goats, sheep, red deer, reindeer, and our 

 extinct gigantic deer, sometimes erroneously styled the Irish Elk," but considered by 

 Nathusius (p. 150) to have belonged to a domestic animal, it is true that the lacrymo- 

 frontal ridge is represented as of great size ; but we must set against the assigning of much 

 importance to this fact the considerations that the drawing is taken from a reconstructed 

 skull, that it is obviously inaccurate in some points, as, for example, like a drawing in 

 S. Miiller's Verhandel. (Taf. 28 bis, fig. 3), in having an extra tooth posteriorly to its 

 canines, and that it may consequently be supposed to be likely to be inaccurate in other 

 particulars also. The fronto-lacrymal ridge is, of course, in the adult underlain by a pro- 

 longation of the frontal sinuses ; it is, however, visible enough in very young specimens 

 of domestic pigs, which show other points of affinity to the Sus indicus long before the 

 frontal sinuses are fully developed; and I am inclined to think it may sometimes, 

 though certainly not always, be detected in very young specimens of Sus scrofa, var. 

 ferus, such as the one figured by Nathusius, I. c. (Taf. i. fig. 1, Taf. iii. fig. 13). Though 

 the fulness of this region is due in the adult partly to its being underlain by frontal 

 sinuses, which are relatively small in the early stages of the animal's life, there 

 is still some justification for regarding this structure as an instance of the retention by 

 the adult of an early structural arrangement; for it is easy to understand that the 

 contour described by the external tables in early youth may be carried out conform- 

 ably by the bloodvessels of the scalp as the animal grows older. A parallel to 

 such a process is furnished to us very frequently, though by no means so nearly 

 universally, by the retention in the adult Sus cristatus of that fulness and convexity of 

 the vertical aspect of the fronto-parietal region which is characteristic of Sus scrofa 



