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FOSSIL REPTILIA OF THE 



The most striking characteristic difference from that species is the vastly superior size 

 of the seemingly allied Flying Dragons from the British Chalk and Wealden. 



In the restoration of the skull of Fterodactylus compressirostris (' Monograph on the 

 Fossil Reptilia of the Cretaceous Formations/ 4to, Part I, 1851, Palseontographical 

 Society's vol. for 1851) I ventured to assign to the mandible a length of 14 inches 

 9 lines (PI. XXVII, fig. 5). This species was represented by two portions of the upper 

 jaw (ib., PI. XXVIII, figs. 8, 9, 10) from the Middle Chalk of Kent, the longest portion 

 being 4 inches in length. Of the nearly allied species, represented by three portions of 

 the lower jaw, discovered by Samuel H. Beckles, Esq., F.R.S., F.G.S., in the 

 Hastings series of the Wealden Formation, west of St.-Leonard's-on-Sea, the restoration 

 figured of half the natural size in Plate II, fig. 8, gives a mandible of between 14 and 15 

 inches in length, and this on the most moderate estimate of the length of the symphysis. 

 In a sketch of a restoration of the jaw, sent to me with the fossils by Mr. Beckles, the 

 length of the symphysis, which he assigns on the basis or analogy of that in Collins's or 

 Cuvier's Pterodactylus longirostris gives a total length of 18 inches to the mandible. 



The parts obtained by Mr. Beckles are of one and the same lower jaw; and, as an 

 extent of above 2 inches of both rami are maintained by a portion of matrix (PI. II, 

 fig. 8, m) in their natural relative position, the angle of convergence is shown ; and this 

 affords a ground for estimating the length of each ramus from the articular surface to the 

 hind part or border of the symphysis at 13 inches, the extent beyond remaining 

 conjectural. 



The specimen includes a portion of the left ramus, 9 inches 8 lines in length (of 

 which the anterior 7 inches are given in PI. II, fig. 1), and two portions of the right 

 ramus, of which the dentary part measures 5 inches (ib., fig. 2) in length, the articular 

 part 2 inches (ib., fig. 5). 



The portion of the left ramus includes the dentary element (ib., fig. 1, and fig. 4, 32) 

 with the anterior part of the splenial element (fig. 4, 31). The dentary includes ten of the 

 hinder sockets (ib., fig. 1, 1, 2, 3, 4, 5), of which the five foremost (ib., 6, 7, 8, 9, 10) retain 

 more or less of their teeth. As the number of these which may have been present in the 

 fore part of the jaw is unknown, I count those which are preserved from the hind end of 

 the series forwards. Prolonging the alveolar border according to a moderate estimate of 

 the symphysis, and supposing the teeth to maintain the same intervals, about eighteen 

 may be assigned to each ramus. 



The border of the hindmost socket (fig. 1, 1) is not prominent as in the rest, and there 

 is room for doubt whether the oval vacuity which indicates the hindmost tooth really 

 contained one. There is none, however, with regard to the next socket (ib., 2), for this, 

 like the antecedent ones, rises at its outlet above the level of the surrounding part of the 

 bone. It projects from the outer part of the thick, transversely convex, upper border of 

 the dentary, and the course of the cavity shows that the tooth must have inclined some- 

 what outward as well as forward from the perpendicular. The long diameter of the 



