LOWER LIAS 7 



those of the Liassic ocean, seem to have swarmed with carnivorous Enaliosaurs. 

 If the Dinosauria were ovo-viviparous, and produced but few young at a birth, 

 the remains from the lower Lias figured in Tab. Ill might be those of a foetus 

 borne by a gravid Scelidosaur to sea during an occasional excursion, and which by 

 some casualty had there perished, and become imbedded, with her progeny, in the 

 muddy bottom of the old Liassic ocean. I have not, however, been able to 

 obtain precise evidence of the proximity of the small bones above described with 

 any of the larger ones attributed to the SceUdosaurus, and bones of more than 

 one small individual might have been expected to occur in juxtaposition if they 

 had perished before birth. The analogy of the crocodile, moreover, would lead us 

 to expect that the newly excluded or newly born Scelidosaur would be of smaller 

 size than the individual indicated by the bones in Tab. III. 



The Skull. Tabs. IV, V, VI. 



The foregoing indications of a Dinosaur in the lower Lias excited speculation 

 as to whether it had been herbivorous, like the Iguanodon of the newer Mezozoic 

 beds, or carnivorous, like the Megalosaur, which has been traced from Wealden 

 down to the " great, Oolite." The structure of the femur pointed the former way, 

 but the proof which the dentition only could give was wanting. 



The persevering encouragement afforded by Mr. Harrison to the workmen in 

 the Lias quarries has, however, been rewarded by the acquisition of the fine 

 specimen of a skull which forms the subject of Tabs. IV, V, and VI. 



The teeth, in their close-set, thecodont implantation, relative size to the jaw. 

 degree of expansion, and general shape of the crown, resemble those ascribed to 

 the Hylaosaurus (p. 21, tab. viii, figs. I — 3, 'Monograph on Wealden Reptilia,' 

 1857) ; but the crown presents the median longitudinal prominence and marginal 

 serrations which bring it closer to the Iguanodont pattern ; and, in the degree in 

 which they depart therefrom, they still more closely resemble the teeth of the 

 Echinodon from the Purbeck,* which may prove to be a small kind, or young, of 

 a Dinosaur. They, however, present different proportions. 



Referring, therefore, the skull in question to the Dinosaurian order, it sup- 

 plies most acceptable information as to the cranial structure of that group, which 

 no previous example from Oolitic and Wealden beds has been sufficiently perfect 

 to impart. 



Of Iguanodon, Megalosaur us, and Hylceosaurus , portions of lower jaw, and 

 mere fragmentary bits of the upper jaw, palate, and basis cranii, are all that have 

 hitherto come to light. But the present specimen is the entire skull, wanting 

 only the fore end of the upper and lower jaws. 



* 'Monograph on the Fossil Lacertian Reptiles of the Piirheck Limestones.' p. 35, 1858. 



