516 PBOCEEDINGS OP THE GEOLOGICAL SOCIETY. [June 25, 



the dental base ; the outer side of the tooth is sculptured like the 

 rest of the bone, but in a less or finer degree (see the magnified 

 view, fig. 5, a). At rather less than a line in advance of this tooth 

 is a minute one like the fourth ; in advance of this is the base of a 

 larger denticle (ib. &), the fracture of which shows a cavity filled 

 by pyritic matrix ; and at a line in advance of this is the fractured 

 hollow base of a smaller denticle : these hollows might at first sight 

 be mistaken for sockets. 



The alveolar border of the left side of the upper jaw (PI. XVI. 

 fig. 2, & fig. 6, magnified two diameters), continued further forward than 

 that of the right side, shows, at a part wanting on the right side, a 

 more advanced tooth (c), of the same shape as the fifth (a) from the 

 hindermost on the right side, but somewhat larger ; its apex is more 

 obtuse and seems to have been worn. This tooth is also a direct 

 continuation of the bone, with the osseous sculpturing more feebly 

 marked than on the jaw, the tooth appearing smooth to the naked 

 eye. The bases of two smaller denticles appear in the 3 lines ex- 

 tent of alveolar border in advance of this tooth. 



Thus we have evidence of about twelve of the maxillary teeth or 

 tooth-like processes — two large, divided by an interval of about 

 half an inch, the rest small or minute — all compressed, triangular, 

 pointed, arming the hinder inch and a half of the alveolar border 

 on each side of the upper jaw. 



This dental character is more distinctly displayed in the corre- 

 sponding parts of the alveolar border of the lower jaw. On the 

 right side (PI. XVI. fig. 1), in an extent of 8 lines from the suture 

 of the dentary (32) with the surangular (3i), are five denticles (fig. 5, 

 magn. 2 diameters) : the hindermost is as minute as the one above ; 

 the next is somewhat larger ; the third (d) is much larger, though not 

 so large as the fifth (a) above, behind which the point of the third 

 below projects. The fourth tooth below (counting forwards) is mi- 

 nute, the fifth (e) suddenly enlarged, especially in length, to 3 lines, 

 with a breadth of base of 1 line ; it is sharp-pointed, directed 

 obliquely upward and forward. These teeth are processes of the 

 bone ; and the outward markings are strongest near the apex. 



In the left dentary (PI. XVI. fig. 2 & fig. 6, magn. 2 diams.), along 

 an inch extent of the hind part of the alveolar border, are three of 

 the larger laniariform teeth (ib. ib. d, e,/), divided by intervals of 

 from 3 to 4 lines, in which are minute denticles. 



The lower laniaries are longer and more slender than the upper 

 ones ; they are similarly directed, with their summits slightly in- 

 clined forward. 



On an estimate of the extent of the dentigerous borders of the 

 jaws at 3 inches, and a conjecture that the larger teeth were con- 

 tinued at the same intervals (as shown in the fossil) to the ends of 

 the restored jaws, there would be ten of these teeth on each side 

 of both upper and lower mandibles ; the intervening denticles would 

 be about double that number (see conjectural restoration, fig. 8, 

 PI. XVI.). 



The strictly avian character of the skull, on which this quasi- 



