744 J. W. HULKE ON AN OS ARTICULARE, 



40. Note on an Os articulare, presumably that of Iguanodon M an- 

 telli. By J. W. Hulke, Esq., P.R.S., F.G.S. (Read March 20, 



1878.) 



More than forty years have passed since the late indefatigable 

 Gideon Mantell's discovery of a tooth first brought to light the 

 former existence of the Iguanodon. Since then the remains of 

 this great Dinosaur have been plentifully obtained from the Wealden 

 districts in Kent, Sussex, and the Isle of Wight ; and of most seg- 

 ments of its skeleton we now possess a better knowledge than we 

 have of the bony frame of any of its larger contemporaries. 



It is of the heads of these Dinosaurs that our knowledge continues 

 to this day very defective. Tooth-bearing portions of the mandibles 

 and maxillae of Iguanodon Mantelli are now to be seen in the prin- 

 cipal public and in some private collections ; but of crania proper 

 which can with much probability be referred to Iguanodon, the only 

 remains known to me are a mutilated base, with side-walls, and 

 several fragments of the vault and sides of the skull in the Eev. W. 

 Fox's collection, obtained near Brixton, Isle of Wight, and the skull 

 which, several years ago, I brought under the notice of this Society, 

 and of which a figure is given in vol. xxvii. pi. xi. of the Quarterly 

 Journal. It came from the Wealden clay at Brooke. 



The articular element of the mandible is one of the missing parts 

 which has escaped recognition (no mandible yet figured, or, so 

 far as I know, in any collection, possesses it) ; and I am happy 

 to have now an opportunity, through the courtesy of Mr. Pox, 

 of bringing before the Society a form of articular bone to which, from 

 intrinsic characters, and also from its gisement, the Iguanodon 

 appears to me to have a paramount claim. 



After several years of fruitless search in every accessible collec- 

 tion for the Iguanodon's os articulare, Mr. Pox, in 1869, submitted 

 to me a bone the skeletal place of which he had not been able to 

 decide ; and indeed, apart from the rest of the mandible, its identi- 

 fication by one who had not specially studied anatomy offered con- 

 siderable difficulty. There could not, however, be any doubt that 

 the bone in question was the detached os articulare of a very large 

 reptilian mandible. Mr. Pox had long possessed three, which, as he 

 afterwards told me, he had obtained from the same localities that 

 had yielded him magnificent mandibular rami of Mantell's Igua- 

 nodon. I suggested at the time to their fortunate possessor that he 

 should publish an account of these valuable specimens; but it 

 appeared to him wiser to wait for additional evidence confirmatory 

 of their really belonging to the Iguanodon. Since then he has ob- 

 tained two others, making five in all, of which four belong to right 

 rami ; and in May of last year he proposed to me to communicate 

 to the Society an account of them. 



Taking the least imperfect specimen as the type (in all the ante- 



