CRETACEOUS FORMATIONS. 3 



Pterodactyle (Monog. cit., Tab. XXVIII, figs. 1 — 4) with the same part of the still 

 larger species from the Green-sand (Tab. I, figs. 1 and 2), to be convinced of their 

 specific distinction. 



The difference is still more marked between Pterodactylus Sedgwickii and Ptero- 

 dactylus compressirostris (Tab. XXVIII, figs. 8, 9, 10). The rapid increase of depth 

 as the jaw extends backward, in Pter. giganteus, Bk. (ib., Tab. XXXI, fig. 1), shows that 

 that comparatively small species cannot be the young of the present truly gigantic 

 Pterodactyle of the Upper Green-sand. I have no hesitation, therefore, in basing 

 on the above-described fossil a new species, at present the largest known in the order 

 of Flying Saurians, which I propose to dedicate to the Woodwardian Professor of 

 Geology in the University of Cambridge, who for forty years has discharged the 

 duties of that office with exemplary zeal and a rare eloquence, has almost created the 

 museum still called (Woodwardian,) and has enriched geological science by original 

 researches which have thrown light on its most obscure and difficult problems. 



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

 present description is the fore part of the jaw figured in Tab. I, figs. 2, a, h, 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 pro- 

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

 proportions of the lower jaw in Pter. giganteus (Monog. cit.. Tab. XXXI, 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, a, b, represents part of the under jaw of Pterodactylus Sedgwickii, the 

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

 Sedgwicldi. 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 (Tab. I, fig. 2, d), showing the same relative position of the 

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



