CRETACEOUS FORMATIONS. 17 



extent of the base of the radial crest in fig. 5 corresponds with that of 

 Pterodactylus suevicus* 



In Ramphorhynchus Gemmingi the radial crest, with a similar short origin, 

 has a remarkable transverse extent, and expands at its termination, so that 

 both upper and lower margins are very concave.f The latter is of much greater 

 relative extent than in the large Cretaceous Pterodactyle (Tab. Ill, fig. 1). The 

 Wealden Pterodactyle (Pter. omis) resembled Ramphorhynchus in the propor- 

 tions of the radial or outer process { g , fig. 5, ' Quart. Journal of the Geol. Soc.,' 

 1845, p. 99). 



The determination of the homologies of the processes from the proximal end 

 of the humerus of the Pterodactyle with those in the bird and crocodile enables 

 one to recognise the specimen (figs. 1 — 3 and fig. 5) as part of the right 

 humerus. 



Fig. 4 is part of the left humerus, from the Upper Green-sand of Cambridge- 

 shire, but was drawn upon the stone without reversing, to facilitate its comparison 

 with fig. 1, from the Middle or White Chalk of Kent, which it resembles in the 

 extent of origin of the radial ridge (b). 



Carpal Bones (Tab. II, fig. 6 ; Tab. IV, figs. 5—9). 



The two bones (Tab. IV, figs. 5, 6, and figs. 7 — 10) correspond in size so 

 much more with that of the distal extremities of the radius and ulna than with that 

 of the same part of the tibia, as to leave a conviction that they are carpal bones, 

 and they afford instructive evidence of the characters of those bones in the 

 Pterodactyle. Specimens of more or less entire, but dislocated, skeletons of the 

 smaller kinds of Pterodactyle from Oolitic strata, especially that of Ptero- 

 dactylus suevicus from the lithographic slates of Wirtemburg,J and that of 

 Ramphorhynchus Gemmingi from the same formation at Eichstadt,§ have demon- 

 strated the presence of at least two large carpal bones, with one or two smaller 

 ones, the two carpals forming a first and second row ; but the figures are too small 

 and indefinite to permit the matching with them of either of the larger and 

 probably better-preserved carpal bones from the Cambridge Green-sand. 



The first to be described is subdepressed, subtriangular in shape, with a general 

 tendency to convexity on one articular surface (Tab. IV, fig. 8), and to concavity 



* Quenstedt, op. cit., tab. i, cr, cl. 



t H. v. Meyer, op. cit., tab. ix. A. Wagner, 'Fauna des Lithogr. Scbiefers,' 4to, 1S5S, taf. xri. 

 % Well described and figured by Professor Quenstedt, in bis treatise ' Ueber Pterodactylus suevicus,' 

 4to, Tubingen, 1855. 



§ H. v. Meyer, op. cit., tab. ix, fig. 1. 



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