MR. W. K. PARKER ON THE OSTEOLOGY OF BAL^NICEPS REX. 293 



the same extent ; but in birds which are flat in this region, as the Heron and the Duck, 

 each nasal is nearly four times as wide as the delicate splint-like process of the pre- 

 maxillar}', instead of being merely the same width as in the Adjutant. Besides this, the 

 extreme height and convexity of the posterior part of the ridge of the broad face of the 

 Balreniceps must be considered, and also the distance between its nasal fossse, as measured 

 from the posterior boundary of each. In the Adjutant this distance is ten lines, in the 

 Balajniceps fourteen, which makes it very probable that each nasal process of the pre- 

 maxillary was, in the young bird, even wider than the nasal. Most birds in which the 

 sutures can be seen show that the upper margin of the nasal passage is almost entirely 

 bounded by the nasal, the posterior margin entirely, and a great part of the inferior 

 margin. In Balseniceps this latter line separates the posterior part of the large pre- 

 maxillary internally, as it passes towards its posterior angle, from the horizontal 

 inferior turbinal, which, with its fellow, forms a nearly perfect palatal floor to the nasal 

 fossae. An arcuate line, its convexity upwards, passing from the middle of the inferior 

 margin of the nasal passage to the point where the maxillary meets the lowest part of 

 the lacrymal and the posterior angle of the pre-maxillary, will indicate, as near as may 

 be, the anterior boundary of the lateral portion of the nasal. 



Fr onto -maxillary hinge. (PI. LXV. figs. 1 & 6.) 



Adhering to our plan of working regionally, we shall leave the ethmoid and eth- 

 moidal hsemapophyses until the pree-maxillte, nostrils, and cranio-facial hinge have been 

 described. 



In the great transverse hinge of the upper jaw on the head, the most external tooth- 

 like process, which passes backwards outside a similar tooth of the frontal going 

 forwards, belongs to the lacrymal, that bone having escaped from its usual connexion 

 with the principal frontal. A third tooth inside these, and which, like the first, looks 

 backwards, belongs to the ' nasal,' and is the outer part of its posterior boundary. This 

 frontal margin is then continued nearly straight towards the mesial line, where about 

 two-thirds of an inch of the hinge belongs to the pre-maxillary. The most projecting 

 part of the hinge is mesial, the pre-maxillary encroaching upon the principal frontal ; 

 and, curious enough, this is the place for the great ball-like process of the Maccaws 

 and Parrots, the cup being made in the pre-sphenoid. The lacrymal and ' nasal ' tooth- 

 like projections, as well as the corresponding parts in the frontal, are evidently coated 

 in the recent state with articular cartilage, whilst the rest of the hinge seems to be 

 something intermediate between ' harmony ' and ' dentate suture.' 



To return to the ' nasal.' Anterior to the hinge this bone is smooth, and gently 

 inclines downwards, the smooth and bevelled surface being about half an inch square ; 

 it then rises, becoming very rough and punctate, and at five-sixths of an inch from the 

 hinge forms the posterior boundary of the nasal fossa. The nostrils are at this part 

 1^ inch apart, but further forwards only an inch of bone separates them. The upper 



VOL. IV. PART VH. 2 T 



