640 



PROP. H. G. SEELEY ON THE EEPTILE 



margin curves downwards and inwards as it extends forward. The 

 fourth alveolus is the only one which displays an indication of tooth- 

 structure. It is the extremity of a compressed arrow-shaped suc- 

 cessional tooth with serrated border, more after the pattern of that 

 seen in Priodontoguathus than in any other genus, but too imper- 

 fect to demonstrate the generic characters. It appears to be more 

 elongated than the teeth of any genus hitherto described. It may 

 pertain to one species of Gratceomus. 



The other fragmentary pieces of lower jaws may or may not belong 

 to one individual. A terminal fragment pertains to the anterior end 

 of the right ramus. Two other and smaller fragments belong to the 

 left ramus ; but they are so imperfectly preserved as to be scarcely 

 worth notice, although they are apparently quite distinct from the 

 species just described, if I may judge from the flatness of the in- 

 ferior surface of the jaw and the flatness of the lower part of the 

 side which was vertical. 



The anterior extremity of the right ramus was loosely attached, 

 by a rough lunate surface about 17 millimetres deep and 8 milli- 

 metres wide, to the ramus on the opposite side. Its extremity is 

 bent a little inwards and downwards — the basal margin being con- 

 cave from in front backward, and the prolongation of the alveolar 

 margin convex. The fragment is 4 centimetres long ; and though 

 upwards of 3 centimetres of the alveolar margin are preserved, 

 I do not recognize with certainty any tooth-sockets. If such 

 exist, they are three in number, and are indicated by small round 

 sockets placed just behind the symphysis ; but as the whole anterior 

 end of the bone is covered with vascular foramina, and there are 

 corresponding foramina external to these possible sockets, it is not 

 improbable that they are foramina also, since they present no dis- 

 tinctive alveolar characteristics. The jaw thickens a little in 

 front here ; it is bevelled, looks obliquely forward, upward, and, 

 perhaps, outward, and has the appearance of having utilized the 

 foramina in the nutrition of a pad. This surface is about 3 J cen- 

 timetres long, and above the symphysis is 13 millimetres wide, but 

 becomes narrower posteriorly, where it terminates on the inner edge 

 of the jaw in a sharp margin, external to which two large oblique 

 foramina appear at intervals, the second of which seems to be ex- 

 ternal to the first tooth-socket, which is compressed from side to 

 side, if it really be a socket, of which there is some doubt. At this 

 point the depth of the jaw is about 2| centimetres. Below the an- 

 terior area described, the upper portion of the side which is smooth 

 begins to be concave from above downwards ; and the lower part of 

 the side which is rugose is here convex, though it may, perhaps, as 

 indicated by a fragment already referred to from the other side of 

 the jaw, become flattened in its posterior extension. The specimen 

 shows no trace of the groove on the inferior margin of the inner 

 side seen in the specimen already described ; and the appearance of 

 a groove in the upper part probably results from fracture. The 

 internal surface is smooth and concave in length. The thickness of 

 the jaw at the posterior fracture is about 11 millimetres; the base, 



