MR. W. K. PARKER ON THE OSTEOLOGY OF BALiENICEPS REX. 307 



Tlie whole bone ascends gently until its lower margin is half an inch above the 

 horizontal palatine plane ; it then descends more rapidly anteriorly, and appears on the 

 palatal floor a little between, but more in front of, the palatine turbinals ; this part is 

 more than half an inch long and rather more than a line in thickness, and is notched in 

 front. The upper part of the descending portion loses its groove, becomes filled with 

 pneumatic foramina, and is rounded and smooth anteriorly. In the Common Hare 

 (Lepus timidus), with its almost obsolete palatine processes of the maxillary and palate 

 bones, its one large palatine foramen, and large, deep, widely-open posterior nares, the 

 vomer descends to the mesial palatine region, becoming thick and broad below, to 

 articulate with the long narrow palatine processes of the pre-maxillaries. This is the 

 most favourable of all creatures in which to see the complete fusion of the posterior 

 lateral laminae of the vomer with the lateral masses of the ethmoid, and to judge how 

 easy it must be for the too rapid extension of the cranio-facial axis to break up the thin 

 vomer during its ossification into distinct pieces (as the cranial roof-bones are often 

 dismembered in Man), such as the 'bones of Bertin' in Man, and their representatives in 

 the Pig, Fox, Chimpanzee, and the Cetaceans. In the Rodentia generally (e. g. Arctomys, 

 Mus, Arvicola, Sec.) the vomer does not reach the palatine plane. 



Palatines, Posterior Nares, and Vomer. (PI. LXV. figs. 1 & 7, pal, p n, v.) 

 The posterior nasal passages in the Balseniceps (and it does not differ essentially 

 from other typical birds) are bounded in front by the palatine turbinals, on each 

 side by the internal margin of each ' palatal,' whilst they are partially separated from 

 each other by the ' vomer,' the partition being comple^^d by membrane. The palatals 

 in Balaeniceps being obliquely placed and meeting behind, the posterior nares are defined 

 by them posteriorly. The entire transverse extent of the palatals in front is two inches 

 and a third, their antero-posterior extent being nearly two inches. 



The coalesced palatines seen from beneath form a large, triangular, deeply and 

 strongly concavo-convex mass of bone ; the posterior nares being, as it were, cut out of 

 the broad anterior base of the triangle, in front of which space there are the palatine 

 turbinals, and along its middle the thin arrested vomer, whilst the apex is notched, 

 truncate, and toothed to receive the pterygoids. Thin and laminar at their origin, the 

 palatines are connected by suture with the pre-maxillaries and maxillaries (with the 

 former internally, and with the latter externally) ; but the middle portion of this suture 

 soon becomes converted into anchylosis. From the internal part of the suture a strong 

 convex ridge, f of an inch long, passes outwards, downwards, and backwards ; the bone 

 above the middle part of this ridge becoming thick and spongy, whilst it thins off 

 behind. Internal and posterior to this broad convex ridge the bone becomes less broad, 

 as it first passes upwards and backwards, and then curves suddenly downwards to meet 

 its fellow and form a strong mesial keel. The hinder carinate part of the palatines, at 

 their line of coalescence, is half an inch in extent. At its front part the mesial keel 

 bifurcates, the bifurcation at each side becop'ing a crescentic portion of the inner margin 



