464 BRITISH FOSSIL REPTILES. 



This specimen confirmed the accuracy of Biicldand's conjecture, which I had doubted, 

 viz., tliat the portion of lower jaw with the series of small lancet-shaped, close-set teeth,i 

 in a second slab of Lias, belonged to the same Pterodactyle as the limb-bones he described ; 

 but it also showed that these teeth, so like those of some Pishes, were limited to the lower 

 jaw, and were associated, in the same mouth, with long, slender, trenchant and sharp- 

 pointed laniaries, projecting with wide intervals, and set in advance ; which kind of teeth 

 had, hitherto, alone been found in the different species of flying Reptiles. 



The chief result of the study of the second discovery of a Pterosaurian in Lias, viz., 

 its evidence of a new generic form {Dmorjjhodo?i) in the order of volant Eeptilia, in 

 addition to Rhamphorhjnclms, von Meyer, and Plerodactylus proper, was noted in the com- 

 munication above cited. 



The third specimen about to be described confirms that taxonomic deduction, showing 

 a combination of the caudal character, mainly differentiating Bhampjhorhynchus from 

 Pterodactyl us, with the dental character above defined. 



I propose first to describe and figure the two specimens yielding the cranial and 

 dental characters of Dimorphodon, and then to attempt a restoration of the Liassic species, 

 D. mac.ronyx. 



The first specimen with the skull is figured in PI. 15. It is on a slab of Lias, mea- 

 suring 11 inches by 7 inches. The right side of the head is exposed :" it has been subject 

 to j)ressure and some degree of dislocation. Certain bones of both wings, and a few 

 other parts of the skeleton are preserved, pell-mell, in this slab, pressed amongst 

 and upon the bones of the head, especially at the back part of the skull. 



The right premaxillary (22), maxillary (21): and nasal (15), are almost in their natural 

 positions, give the profile contour of that part of the skull, show most of the teeth of the 

 right side upper jaw, and reveal the singular expansion of the nasal («) and antorbilal (a) 

 vacuities. The alveolar part of the left maxillary (S'), with its ascending postnarial 

 branch has been pushed obliquely downward, with fracture, but without much 

 displacement, of the beginning of the alveolar ray, the inner surface of which is 

 exposed. 



The mandible (.32) has been dislocated and pushed below the place of its articulation 

 with the tympanic (28) : the left ramus has also been subject to the same force which has 

 dislocated that side of the upper jaw ; the hind part of this ramus is obliquely depressed, 

 so as to expose the inner surface (32). 



The anterior entire or undivided part of the premaxillary (22) is about 2 inches in length, 

 and \\ inch in vertical height at its back part: it contains four pairs of teeth, which are 

 the largest and longest of the series. The foremost tooth (1) is terminal, with a crown 

 5 lines in length, rather over 1 line in breadth (fore-and-aft) at its base ; it is subcompressed, 



1 Bucklaiid, loc. cit., pi. x.wii, fig. 3. 



- Tlie specimen lias been drawn, in PI. 15 {Pterosauria), without reversing. 



