30 H. Gr. SEELEY ON EHAMPHOCEPHALUS PRESTWICHI. 



there is here evidence of a cerebral elongation to whicli no other 

 Pterodactyle even approximates ; and it is difficult to believe that a 

 brain- cavity so long and narrow, as shown by the median constric- 

 tion, could have contained a brain of Avian plan such as is evidenced 

 by almost every specimen from Solenhofen in which an internal 

 mould of this region is preserved, as may be seen in the museums at 

 Munich, Heidelberg, and Haarlem. 



Secondly, I do not remember in any other Pterodactyle any thing 

 like so great a constriction of the frontal region between the orbits ; 

 thirdly, the sutures between the bones are better marked than in 

 any other Pterodactyle which I have examined ; and, fourthly, the 

 j)lan of structure of the roof-bones of this skull is so entirely Eepti- 

 lian as to suggest the existence of Ornithosaurian animals of lower 

 grade than any which I have hitherto seen. The slender material 

 does not, however, justify speculation ; and it is quite possible that 

 this may prove to be a genus closely allied to some of those animals 

 for which the name JRhamphorhyncJius has been appropriated ; and 

 I shall be quite prepared to find that all the Ornithosaurians 

 from Stonesfield belong to this or an allied genus which had JRham- 

 'phorhynchus for its nearest ally, and which resembled that genus in 

 the characters of the postorbital arches. 



There are indications, however, in the Stonesfield fossils of impor- 

 tant differences from the German types now included in RTiam- 

 pJiorhynchiis in the characters of the mandible and dentition, and the 

 relatively large size of the hind limbs, the femur being, in one of 

 these animals, 94 millimetres long, while the tibia has a length of 

 90 millimetres. This is far beyond the size of any species of 

 JRhamphorhynchus^ and, indeed, is only to be paralleled in Dimor- 

 jpTiodon and the larger short-tailed German Pterodactyles, which 

 have long hind legs and form the genus Cycnorhamphus. The wing- 

 phalanges in these Stonesfield animals are, however, unusually long, 

 longer than in any German species except perhaps Pterodactylus 

 vulturinus, which is imperfectly known. The first phalange of the 

 wing-finger of the largest Stonesfield specimen is nearly 5 inches long, 

 while the second and third phalanges measure about 7| inches each, 

 while the fourth is 6 J inches long. But the Oxford specimens 

 appear to indicate, from the different proportions of cervical verte- 

 brae, lower jaws, and bones of the fore and hind limb, two or three 

 well-defined species. To these may be added another from the 

 Great Oolitic of Sarsden, of which the mandible has already been 

 figured in this Journal by Prof. Huxley*. Although in the latter 

 specimen nearly the whole skeleton appears to have occurred in the 

 same spot, no trace of a long tail of the Bliamjpliorhynchus type has 

 been met with. Among the Stonesfield specimens the sacrum con- 

 sists of at least five vertebrae, and there are cervical and dorsal verte- 

 brae, including the atlas, which apparently is not ankylosed to the 

 axis, but no trace of a tail. These facts, taken in conjunction with 

 the relatively large size of the hind limb and sacrum and the cranial 

 differences, will, I believe, justify me in instituting a new genus for 

 this cranium and the other Stonesfield Ornithosaurs. 

 * Quart. Journ. Geol. Soc. yoI. xv. p. 658. 



