﻿Yol. 64.] METBIORHYNCHUS BRACHYBHYNCHUS. 355 



were two bones, and that they were fused together perhaps at a 

 comparatively early stage in the animal's growth ; but there remains 

 still an interesting question as to whether the vomers were not 

 represented by a single bone in the Metriorhynchidae. I can find no 

 description of the vomers in any work dealing with this genus. It 

 is to be hoped that further discoveries and investigation may settle 

 the point. 



In order to simplify description, I propose to treat the vomerine 

 element as one bone, for all practical purposes T-shaped in section. 

 Towards its anterior end, though imperfect in the specimens here 

 described, it was probably coextensive with the palatines. It divides 

 the nares from that point to their posterior outlets. Anteriorly the 

 nares Avere enclosed by the maxillae, as in the modern Gharials. The 

 perpendicular of the T is wedge-shaped, its point interlaced between 

 the median walls of the palatines, while the horizontal arms extend 

 to meet the outer walls of the palatines. The upper surface of these 

 arms is grooved. This groove, shallow at first, deepens a little 

 farther backwards, with high ridges on either side against which 

 the outer walls of the palatines lie ; it dies out gradually antero- 

 posteriorly, the outer arms of the bone curving downwards and 

 underlying the outer walls of the palatines. At the point where the 

 outer walls of the palatines diverge, the * vomerine bone ' begins to 

 taper away to a point some 25 mm. behind the palatines. The 

 divergence of the outer walls thus leaves a gradually-widening 

 open canal in the palatines, which however was covered in by the 

 anterior end of the pterygoid. The outer walls of the palatines 

 present a striated surface which lay in conjunction with a similar 

 one in the pterygoids, while the pterygoids were evidently united 

 to the ' vomerine bone ' as far as the posterior end of the latter. The 

 ' vomerine bone ' thus formed a ridge dividing the roof of the 

 posterior nares. By the courtesy of Dr. A. Smith Woodward, 

 Keeper of the Geological Department in the British Museum 

 (Natural History), I have been enabled to examine various speci- 

 mens in the IS'ational Collection. In an almost complete skull of 

 Pelagosaurus typus (Bronn), Catal. N'o. 32599, which is figured and 

 described by Deslongchamps,^ there is a marked ridge noticeable in 

 the roof of the posterior nares. Deslongchamps considers that it 

 marks the line of division between the two pterygoids anteriorly, 

 as he remarks is the case in the other Teleosauriaus. It is a 

 question, however, whether this ridge does not form part of the 

 vomers, as in the instance of Metriorhynchus. 



Among the specimens of Steneosaurus in the British Museum, 

 I cannot find one that shows this part of the palate clearly 

 enough to say whether such is the case also in other species of 

 the Teleosaurian Crocodiles, although in one specimen the bones 

 as preserved render it more than probable. Deslongchamps makes 

 no mention of the vomers ; and, except in the case of Pelagosaurus^ 

 he does not figure any such ridge. 



^ E. Eudes-Deslongchamps, 'Le Jura Normand' pt. i (1877) p. 26. 



