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Show 468 DR. J. V. HAAST ON ZIPHIUS NOV^E-ZEALANDI^;. [June 6, Mandible. ft in Length of ramus 2 8*50 ,, of symphysis 7*46 Vertical height of ramus at coronoid process 6*40 Apex of mandible, projecting beyond apex of rostrum (restored) 1*62 Mandibular tooth (right), length 2* 12 „ „ greatest breadth 0*72 „ weight 184 grains. >> It will be seen, in comparing these dimensions with those of the skull from Chatham Islands, figured and described by Dr. Hector, that it is larger and more developed, with the exception of the two mandibular teeth, which are much smaller and in the Chatham-Island specimen are evidently designed for other purposes. The rostrum, of which the point is broken off, is of small dimensions when compared with the posterior portion of the cranium, its point being slightly turned to the right. This point was shattered into such a number of small pieces that, after maceration, it was impossible to secure them all. The same was the case with the point of the lower jaw, so as to suggest to us that the animal had struck the reef and thus injured so considerably that portion of its frame. The premaxillaries are two thin bones which run parallel in their anterior portion. They here curve inwards, so as to form a semi-cylindrical excavation, running along the whole rostrum as far as the septum narium. Before reaching this, however, they alter somewhat their general form, the rounded edge disappearing, the bones now showing a plane rather concave surface, and, gradually rising near the posterior end of the nares, unite here with the nasal bones, by which a high crest is formed. For about one third from the point both sides of the premaxillaries are alike, after which the right one becomes much broader than the left one ; and, passing over the median line of the skull to the left, the skull now becomes very unsymmetrical in its central portion, so that the opening of the nares is displaced to the left. Moreover the uppermost portion of the right premaxillary, besides being broader, is much higher than the left one-a peculiarity to which also the nasal bones conform, the right one being considerably higher than the left one. The prefrontals (of Owen) begin 6*5 inches from the anterior point of the rostrum, gradually widening to one inch, being slightly concave in the centre for a length of 8 inches. They then gradually flatten for a distance of one inch, after which they become convex until they rise and form the thin ridge of the septum narium. The latter is wedged in its anterior portion against the left premaxillary, and, continuing its direction to the left, joins then obliquely the nasal bones. In the centre of the nares, the septum narium is excavated for a depth of nearly 2 inches and a width of 1*20 inch, the bone having here a very sharp edge. |
