468 DR. J. V. HAAST ON ZIPHIUS NOV/E-ZEALANDI^. [June 6, 



Mandible. ft • 



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 dimen- 

 sions 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 unsym metrical 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. 



