Dr. Francis Baron Nopcsa — British Dinosaurs. 205^ 



I am aware, the best evidence that can be brought forward in favour 

 of the newer interpretation. A comparison of this predentary bone 

 with the one of Mochlodon and other Predentata, as figured in my 

 third paper on Transylv'anian Dinosaurs, is equally interesting, and 

 the gradual prolongation of this bone along the line Camptosaurus, 

 Telmatosaiirus, and Trachodon may perhaps be termed as a sort of 

 dolichocephaly due to the cursorial habits of these Phytophagous^ 

 reptiles. •« 



Prcemaxillary. No doubt has hitherto been expressed regarding 

 the statement that the front part of the jaw in Iguanodon was 

 covered with a horny beak, and therefore an examination of the 

 tooth-bearing prsemaxillary in Hypsilophodon was also one of the 

 tasks that had to be accomplished. 



On the top of the well-preserved preemaxillary of one skull 

 (Hulke, 1882, pi. Ixxi, fig. 1), soon a small but pronounced rugosity 

 was detected, and it was at once highly suggestive that this might 

 be the place whence that dermal ossification originated which, 

 spreading by and by over the whole prsemaxillary, gradually 

 formed the beak of the Orthopodous Dinosaurs and suppressed the 

 function of some teeth. That this beak did, however, not yet act 

 effectively in Sypsilophodon is, I think, proved by the presence 

 of the well-developed prsemaxillary teeth. As placed on the front 

 part of the prsemaxillary the rugosity mentioned is at the same 

 time exactly on the place where in some reptiles and birds the 

 Eischwiele of the German author appears, and the idea that this is 

 more then a mere coincidence is perhaps not to be disregarded 

 altogether. 



Dermal ossifications (armour). Contrary to what we know of 

 Iguanodon, Hypsilophodon was surely clad with a thin but a well- 

 developed dermal armour, consisting of comparatively large yet 

 thin and flat, feebly punctured bony plates. I managed, at least, 

 to detect in more than one specimen some plates always showing 

 the same sort of feebly grooved sculpture, and never referable to- 

 any part of the endoskeleton itself. A good sketch of such plates 

 is given in one of Hulke's figures, and in p. 207, Fig. 4, of this 

 paper the grooved markings also come out pretty well. This dermal 

 armour is, again, a character in which Sypsilophodon approaches 

 more closely the armour-clad Stegosaurs and Ceratopsia than any 

 other Ornithopodous Dinosaurs. 



Ossified dorsocaudal tendons. The first figure of ossified dorso- 

 caudal tendons in a Dinosaur dates back to the year 1849, and is 

 a figure representing parts of the tail of Hylceosaurus. Later on- 

 the same elements were mentioned by the Eev. W. Fox in Polacanthus 

 {Illustrated London Neivs, 1865). Again, in 1882 a figure and 

 a short remark on these curious objects was given by Hulke in his 

 Hypsilophodon paper, and in 1887 they were refigured very clearly 

 in his paper on Polacanthus. In the same year (1887) came finally 

 L. Dollo's paper mentioning them in Iguanodon and dealing with- 

 their physiological value. Thus ossified dorsal tendons are present 

 in all the British Prsedentate reptiles, with the sole exception of the 



