WEALDEN PTERODACTYLES. 543 



vertically and deeper in Cohb. clavirostris, where it is below the alveoli of the teetli ( «, «). 

 The convexities (/, /) on each side of this depression are the fore parts of the sockets of the 

 second pair of teeth, not of the first pair, as in Criorhi/nchus shims {Pter., PI. 11, 

 fig. 3, a). The sides of the fore part of the premaxillary in Coloborhyiichus clavirostris 

 converge, with a slight vertical concavity, to the narrow but obtuse upper border of the 

 skull; the same sides also converge as they recede in a slighter degree, but so that the 

 breadth of the upper jaw behind the sixth pairs of teeth (ib., PI. 19, figs. 1 and 4,/,/) 

 is less than two thirds the breadth behind the second pair of teeth (ib. ib., b, b, fig. 4), 

 whence the name clavirostris (' club-snout ') proposed for the present formidable species 

 of Wcalden Pterodactyle. 



The fore part of the bony palate, between the teeth of the second pair (ilj., ib., fig. 4, b,h), 

 is transversely quadrate and flat (ib. ib., fig. 4, k). Behind this tract the mid third only 

 of the palate retains its level, the two side thirds subsiding (as it seems when looked 

 down upon) into shallow channels, which expand and arc continued into the slope rising 

 to the sockets of the fifth («) and sixth (/) teeth, leaving the prominent narrow raid tract 

 to represent, as it were, the bony palate ; this part has projected below the level shown 

 between the fourth pair of teeth, behind which the thin compact wall is broken away, 

 exposing the widely cellular structure. A similar abrasion affects the upper border of the 

 skull (beyond i, fig. 1, PI. 19). 



The first or anterior pair of teeth (ib., «, «) bears the same relations of size to the 

 second (5) and third («) pairs as in Criorhi/nchus sivms, and may be homologous with the 

 first pair in that species (P/er., PI. 11, fig. 1, a) though differing so much in position 

 and direction. In the present specimen of Colohorhynchns clavirostris the crown of the 

 first, as of the second, tooth is broken off at the outlet of the socket. The shape of this 

 outlet is a full ellipse (PI. 19, fig. 2, a, a) ; the long diameter, of 8 m.m., is vertical ; the 

 short diameter, of 6^ m.m., is transverse. The size and shape of the five following 

 teeth are shown in fig. 1 ; for, as is common in Pterodactyles, the sockets open obliquely 

 upon the outer part of the alveolar border, and in the present species with a nearer 

 approach to verticality than is usual (compare PI. 19, fig. 1, with PI. 11, fig. 1. 



The present unique evidence of one of the most extraordinary of the extinct order of 

 volant Beptilia was discovered by S. H. Beckles, Esq., F.R.S., in the Hastings Series 

 of the Wealden. 



The humerus of the Ftcrodactylus sylvestris, Ow.,' from the Tilgate Wealden, though 

 larger than those next to be described, must have belonged to a smaller kind of Pterosaur 

 than that represented by Mr. Beckles's fossil. 



' 'Quarterly Journal of the Geological Society of London,' No. C, 184G, p. !)!), figs. 5, 6, 7. 



6 b 



