1845.] OWEN ON SUPPOSED BIRDS' BONES IN THE WEALDEN. 101 



I conclude, therefore, that the Wealden fossil (fig. 3) is the proxi- 

 mal end of the left humerus of a Pterodactyle : and since the other 

 fossil from the Tilgate strata (figs. 1 to 4) is the distal extremity of a 

 left humerus, presenting the same degree of approximation to that 

 part in the bird, but with differences irreconcileable with their iden- 

 tity, and which are most likely to be such as will be found in the 

 same part in a Pterodactyle ; and since the fossil (figs. 1 to 4-) cor- 

 responds precisely in its proportions and the size of the shaft with the 

 fossil (figs. 5 to 8), it is highly probable that it is part of the same 

 bone ; and it is more than probable that it has belonged to a Pterodac- 

 tyle, and not to a bird : and thus it appears that an affirmative reply 

 must be returned to the sagacious inquiry by Dr. Buckland, whether 

 "the bones discovered in the strata of Tilgate forest may not, on 

 more careful examination, prove to belong to the Pterodactyle*." 



The Wealden fossils here commented on formed part of Dr. Man- 

 tell's valuable collection and are in the British Museum. 



The species indicated by the highly interesting fossils, viz. the 

 proximal and distal end of the humerus above described, must have 

 been about one-third larger than the Pterodactylus macronyx from 

 the lias of Lyme Regis, described by Dr. Buckland in the 3rd vol. 

 of the 2nd Series of the Society's Transactions, p. 217 ; and it was 

 probably as large as the Pterodactyle from the chalk exhibited by 

 Mr. Bowerbank at a meeting of the Society in May lastf . 



This latter discovery has very naturally suggested a doubt respect- 

 ing the described Ornitholites from the chalk, analogous to that ex- 

 pressed by Dr. Buckland with regard to the supposed Ornitholites 

 from the Wealden, and the question may now be urged with greater 

 force, since the re-examination of the supposed Wealden Ornitholites 

 has tended to prove them to belong to the Pterodactyle. If only the 

 shafts of hollow, long bones, like that figured in the Geological 

 Transactions, 2nd Series, vol. vi. pi. 39. fig. 1, had been discovered 

 in the chalk, the idea of their having belonged to Pterodactyles 

 might be admissible ; notwithstanding the prodigious size which, in 

 that case, must have been attributed to the species of Volant Reptile 

 of the cretaceous epoch ; but the evidence of a bird in the chalk 

 formation rests upon a much more characteristic bone, the distal 

 trochlear end, e.g, of a tibia, a figure of which is given in the plate 

 above-cited, fig. 2. 



This form of the lower end of the tibia is quite peculiar to Birds, 

 and relates to the equally peculiar absence of distinct tarsal bones ; 

 these bones being confluent with, and apparently forming, the simple 

 superior extremity of the tarso- metatarsal bone in the bird. In the 

 Pterodactyle there is a true tarsus, consisting of two larger ossicles 

 in the first row, and of two or three in the second row, like those of 

 Lizards, and the distal end of the tibia is modified conformably. 



I have recompared the specimens originally submitted to me by 

 the Earl of Enniskillen, and described as the remains of a longi- 

 j)ennate bird in the Society's Transactions X ; and I cannot, at present, 



* Geol. Trans. 2ii(l Series, vol. iii. p. 220. t Sec auto, p. 7. 



X 2nd Series, vol. vi. \>. ill, and pi. xxxix. 



