CRETACEOUS PTERODACTYLES. 381 



The next fossil selected from the Pterosaurian series of Green-sand fossils for 

 present description is the fore part of the jaw figured in PL 7, figs. 2, a, b, c, d. 

 This contains about the same number of sockets in the same extent of jaw as in fig. 1 ; 

 and the last four sockets present about the same extent of interspace, with the same 

 diminution of size, as compared with the two preceding sockets. But the walls of 

 these sockets form no lateral expansion, the depth of the jaw is less, and the flat sides 

 converge to a sharper ridge, fig. c; the aspect of the sockets is also more obliquely out- 

 ward, the interspace between the pairs is narrower, and this is traversed by a median 

 groove ith of an inch across, fig. b. Were this specimen a part of an upper jaw, it would 

 indicate a distinct species from Pterodactylus Sedgwickii, as exemplified by fig. 1 ; 

 but I regard fig. 2 as being the fore part of a lower jaw, and consequently as most 

 probably belonging to the same species. The minor depth of the bone accords 

 with the proportions of the lower jaw in Pter. gicjanteus (PI. 6, figs. 1 and 2) 

 and the sockets are directed more obliquely outward, as they likewise are in the 

 lower jaw of Pter. giganteus, as compared with the upper one of the specimen of that 

 species, in which both jaws of the same head have been preserved. In the belief, there- 

 fore, that fig. 2, «, b, represents part of the under jaw of Pterodactylus Sedgwickii, the 

 median groove on the upper or oral surface of the prolonged ' symphysis mandibulfe' (fig 

 2, b) suggests that it may have served to lodge a long filiform tongue, perhaps 

 bifurcate at the end, as in the Leptoglossal Lizards of the present day. The same thin 

 outer wall, and capacious cavity filled by matrix, and probably in the living reptile by 

 air, characterise the lower (fig. 2, c), as they do the upper, jaws of Pterodactylus 

 Sedgwickii. In one of the sockets of the lower jaw part of the hollow base of an old 

 tooth is preserved, with the sharp slender point of a new tooth projecting from the 

 inner side of the socket (PI. 7, fig. 2, d), showing the same relative position of the 

 matrix of the successional tooth, as may be observed in the existing Crocodile. 



Pterodactylus Fittoni, Owen. Jaws and teeth, PI. 7, figs. 3, 4, 5. 



Figure 3, a, b, &c., shows the fore part of the upper jaw of a Pterodactyle, with the 

 first and second pairs of alveoli. In the minor depth of the jaw, compared with its 

 basal breadth, in its more obtusely rounded upper surface, and in the greater extent 

 of space between the alveoli of the same size, this maxillary fragment indicates a very 

 distinct species from the Pterodactylus Sedgwickii, but one probably not much inferior 

 in size. I propose to dedicate it to my friend. Dr. Fitton, F.R.S., one of the founders 

 of the Geological Society of London, and who may be regarded as the discoverer of 

 the system now called " Neocomian," which includes the Green-sand matrix of the 

 Flying Reptiles under consideration. The sockets in the fragment (fig. 3) may 



