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XXIY. An Attempt at a complete Osteology of Hypsilophodon Foxii; a British 
Wealden Dinosaur. 
By J. W. Hulke, F.R.S. 
Received January 16,—Read January 26, 1882. 
[Plates 71-82.] 
The dinosauria are peculiarly interesting and instructive on account of the combina¬ 
tions in their skeletons of structures which now only occur separately in those of extant 
Sauropsida; and also on account of their forming a link between more specialised 
.Reptiles and Birds.* The need of such an osteology of a Wealden dinosaur as 
might serve for a type and aid to those who are working out our fossil reptiles, long 
felt, has lately become increasingly urgent through the discoveries in the United 
States of large numbers of remains in such preservation and abundance as to make 
their reconstruction a relatively light task. Some of the members indicated by these 
remains resemble certain of our Wealden fauna, of which our knowledge is very 
imperfect and scanty, so that a strict comparison of the American and British Wealden 
forms appears likely to throw much light upon the latter.t Unfortunately our own 
material does not yet exist in a form available for this purpose; for although a very 
large number of memoirs have been written on the dinosauria of our Cretaceous 
and Wealden formations, nothing approaching to a complete osteology of any one 
of them based on the study of remains recovered from British Cretaceous and 
Wealden formations has yet been published. The reason is not far to seek. In our 
Wealden beds their remains are usually so scattered, disconnected, and not seldom 
mutilated, that their identification and reconstruction are exceptionally difficult. As 
regards Iguctnodon Mantelli a complete osteology may be expected from Belgian 
workers whenever the magnificent remains in the Musee d’Histoire Naturelle at 
Brussels, obtained in 1878 from an extension of the Wealden formation at Bernissart, 
shall have been wrought out—a task which I am authoritatively informed is not likely 
to be accomplished for several years. But with respect to Hypsilophodon something 
* Huxley, “Dinosauria and Birds.” Quart. Journ. Geol. Soc, 1870, p. 12. 
t In illustration of this may be cited the resemblance between Hctdrosaurus, Leidy., Agathaumus , Cope, 
and Iguanodon Mcmtelli; between Lcelaps and Megalosa/u/tus Bucldandi; between Titanosaurus, Atlanto- 
sanrus, Marsh, Gamamsaurus, Cope, and Ornithopsis , Seeley (Syn. Eucamerohis, Hulke, Bothriospondylus, 
Owen, Chondrosteosaurus , Owen) ; between Laosciunis , Marsh, and Hypsilophodon, Huxley. 
