﻿FOSSIL REPTILIA OF THE 



A. — Pterodaciylus Daviesii, Owen. 

 Symphysis Mandibular, and Teeth (Plate I, figs. 5 and 6). 



That this fossil, which is figured of the natural size from the lateral (fig. 5) and oral 

 (fig. G) surfaces, is the fore part of the symphysis of a lower jaw, and not that part of the 

 palate of the upper jaw, is shown by the medial groove in place of the medial ridge on 

 the surface of the bone which was next the mouth, which surface is here on the upper 

 part of the bone and may have served to lodge and facilitate the movements of a 

 cylindrical protrusile tongue. The character of the palatal surface of the upper jaw is 

 exemplified in Pterodactylus Cuvieri (Monogr. cit., 1851, PI. XXVIII, fig. 4); in 

 Pterodaciylus compressirostris (ib., ib., fig. 10) ; in Pterodactylus Sedywickii (Monogr. 

 cit., 1859, PI. I, fig. 1 b) ; and in Pterodactylus clavirostris (PI. I, fig. 4, of the present 

 Monograph). The grooved character of the oral surface of the mandibular symphisis is 

 shown in Pterodactylus Sedywickii (Monogr. cit., PI. I, fig. 2 b). 



The angle of convergence of the two rami of the lower jaw to the symphysis in 

 Pterodactylus sayittirostris (PI. II, fig. 8) renders it improbable that the sides of that 

 symphysis would run parallel for the extent shown in PI. I, fig. 6, or that the 

 symphysis would terminate so obtusely. Moreover, the five pairs of sockets, with bases of 

 teeth, in the fossil representing Pterodactylus Daviesii, indicate teeth of smaller size and 

 closer disposition than in the mandible of Pterodactylus sayittirostris. The foremost 

 pair of sockets (ib., figs. 5 and 6, a) are less elliptical than the rest. The base of the 

 tooth retained gives an almost circular section ; the outlet of the socket is directed more 

 obliquely outward than those of the others, and the crowns of the teeth were, probably, 

 more divaricated in this foremost pair. The sections of the bases of the teeth in the 

 sockets b — e give a fuller ellipse than the outlet of the sockets themselves. The outer 

 surface of the bone is smooth and even, the upward curve from the under margin of the 

 symphysis is gradual, as shown in fig. 5. 



This specimen was discovered in the ' Gault ' at Folkestone, by Mr. William Davies, 

 of the British Museum, to whom, in acknowledging much useful assistance, I have 

 pleasure in dedicating the species of Pterodactyle indicated by the present fossil. 



