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Show 342 DR. ST. G. MIVART ON THE ARCTOIDEA. [Apr. 21, enclose the alisphenoid canal, and, almost from its apex, a strong column of bone which runs backwards, extending behind the foramen ovale, which it quite converts into a canal. The auditory bulla, although, from the flat surface which it presents, it scarcely merits the name, yet may be perceived to show the same essential character as in the Weasels, which is, that it rises suddenly on the inner side at once to its greatest prominence, and is then flattened off towards the meatus, which is rather prolonged. The course of the internal carotid artery, as indicated by the canal excavated for it in the bone, is as follows : It enters by a true canalis caroticus excavated in the bone of the ear, commencing quite behind, in the same fissure in which open the foramen jugulare and the aperture, through which the nervous vagus issues from the skull, and, extending forwards in a slightly arched direction, again emerges anteriorly, and, curving round, enters the cranium in a backward direction, through a round foramen between the sphenoid bone and that of the ear, close to the aperture from which the Eustachian tube would issue, and corresponding to the foramen lacerum anterius ; there is a distinct foramen glenoideum, although opening rather more inwardly than usual; the mastoid and paroccipital processes are both largely developed, and, owing to the very slight projection of the auditory bulla, stand out very distinct and prominent; the foramen condyloideum anterius occupies an exposed situation ; the foramen condyloideum posterius I have never seen in any skull but the human, and here it is said to be sometimes wanting. The characters presented by the lower jaw in the Bears are essentially those most usual, though not quite constant, among the Weasel group; the angular process is pushed up very near to the condyle, and much flattened beneath ; the form of the coronoid process is somewhat that of the true Weasels, but owing to the jaws being in the Bear more pushed forwards, relatively to the situation of the cranial cavity, than in the Weasels, this process is more pushed backwards to meet the temporal muscle. With regard to the little process projecting beneath and anterior to the angle of the jaw, it is a mere superaddition, which appears again in Cercoleptes, as also in Otocyon and Nyctereutes, when it has the form of a large vertical lamella, projecting from the lower surface of the jaw; it is also seen like a second angular process in the Seal, so that I should not feel inclined to assign to it more than a generic value. " In the Mustelina the pterygoid appendages very seldom manifest any tendency to form a fossa, although in many species the outer surface is rough and marked with ridges for muscular attachment; from behind is continued most usually a ridge which runs backwards and outwards along the lower and posterior margin of the foramen ovale. This group is constantly marked by the entire absence of the alisphenoid canal. In the remaining characters this group presents no essential difference from the Bears ; the commencement of the canalis caroticus is usually near the middle of the inner side of the auditory bullae, and anteriorly the vessel does not again quite reach the outside of the cranium, simply showing itself at the |