﻿6 



FOSSIL REPTILIA OF THE 



The articular concavity (fig. 6, a ) is transversely extended, chiefly by the production 

 of its inner wall (ib., b) ; its upper boundary is sinuous by a backward production of its 

 mid part ; the upper surface in advance of the cavity is smooth and gently convex across 

 it narrows to the ordinary thickness of the ramus about an inch and a half in advance of 

 the articulation. In this extent it shows no trace of a coronoid rising. The inner 

 surface is impressed with a deep longitudinal cavity (ib., fig. 7, c). 



According to the usual proportions of the upper and lower jaws of Pterodactyles, 

 the premaxillary of the present species must have been twice, or nearly twice, the depth 

 or vertical diameter of the portion of that bone of Pterodactylus compressirostris (figured 

 in PI. XXVIII, fig. 8, of Monogr. cit.). Both upper and lower jaws of Pterodactylus 

 sayittirostris must have been broader, less compressed, than in the Cretaceous Pter. 

 compressirostris. 



The value of a symphysis mandibuli, with its natural anterior termination, like that of 

 the Gault species {Pterodactylus Daviesii), is its demonstration of a character determinative 

 of the genus of Pterosaurian. Were it produced into a slender-pointed edentulous style, 

 or ' rostrum,' it would lead to a reference of the species to Von Meyer's genus Bampho- 

 rhynchus and Family ' Subulirostres. n The opposite extreme is shown by the thick 

 obtusely terminated snout, as if it had been cut short, giving the character of the Ptero- 

 saurian family Truncirostres? The species of this family which have the foremost pair of 

 teeth projecting forward in the upper jaw from the truncate surface at a higher level than 

 the alveolar border form the genus Coloborhynchus? 



B. — ColoborJiynchus clavirostris, Owen (Plate I, figs. 1 — 4). 



In two species of these large Pterodactyles from the Cretaceous series, viz. Colobo- 

 rhynckus Cuvieri, from the Middle Chalk of Kent, 4 and ColoborJiynchus Sedgwickii? from 

 the Upper Greensand of Cambridge, the anterior pair of teeth of the upper jaw project, as 



1 ' Palseontographica,' Heft i, 4 to, 1846. 



2 Mihi (Truncus, cut short). 



3 <:oA.o/3os, stunted ; pvy\os, snout. I have no evidence, and Mr. Seeley gives none, of such departure 

 from the Pterosaurian type of hand as would justify the term Ornithocheirus proposed by Mr. Seeley for 

 Pterodactylus Sedgwicki'm his ' Ornithosauria,' 8vo, 1870, p. 112; or the term Ptenodactylus previously 

 proposed by Mr. Seeley for the same Pterodactyle in the ' Index to the Fossils, &c, in the Woodwardian 

 Museum,' 8vo, 1869, p. xvi. 



4 ' Monograph on the Fossil Reptilia of the Cretaceous Formations,' Part I (Palseontographical 

 Society's volume for year 1851), p. 88, PI. XXVIII, figs. 1—7. 



5 Ib., ib., 4to, Supplement No. I (Pa)eeontographical Society's volume for year 1857), p. 2, PI. I, 

 figs. 1, a — d. 



