22 FOSSIL REPTILIA OF THE 



dentine, consisting of the calcified remains of the pulp. The dentine differs, like that 

 of existing Lacertians, from the dentine of the Iguanodon in the entire absence of the 

 numerous medullary canals which form so striking a characteristic of the more gigantic 

 Wealden reptile. The main dentinal tubes are characterised by the slight degree of 

 their primary inflections ; they are continued in an unusually direct course from the 

 pulp-cavity to the outer surface of the dentine, at nearly right angles with that surface, 

 but slightly inclined towards the expanded summit of the tooth. They are chiefly 

 remarkable for the large relative size of their secondary branches, which diverge from 

 the trunks in irregular and broken curves, the concavity being always towards the 

 pulp-cavity. In most parts of the tooth, the number of these branches obscures even 

 the thinnest sections. 



The ossified pulp exhibits the parallel concentric layers of the ossified matter 

 surrounding slender medullary canals, and interspersed with irregular elliptical 

 radiated cells, affording the usual characters of the texture of the bone in the higher 

 reptiles. 



From the form and structure of these teeth, it may be inferred that they have 

 belonged to a Dinosaurian reptile ; not so strictly phytiphagous as in the Iguanodon, 

 but probably having a mixed diet. 



In reference to the size of both the fragment of jaw and of the teeth, there is about 

 the same proportion between them and the known remains of the Hylasosaurus, as 

 between the jaw with teeth of the Iguanodon and the vertebrae and limb-bones of that 

 colossal Dinosaur. The structure of the osseous substance of the portion of jaw 

 fio-ured m T. VIII closely accords with that of the known bones of the Hylseosaurus. 



Having, therefore, demonstrated that the above-described mandibular and dental 

 fossils of the Wealden do not appertain to the Iguanodon, nor to the Cylindricodon, it 

 has appeared to me more to the interests of palaeontology to refrain from adding to its 

 catalogues a new name, which at present could signify nothing but the bare possibility 

 that the grounds for approximating the fossils in question to the Hylaeosaurus may 

 prove not to be valid. 



Dermal Scutes. T. X. 



Unequivocal evidence that a dermal skeleton, analogous to that in the recent 

 Crocodiles, was developed in the Hylseosaurus, has been afforded by the discovery of bony 

 scutes in the mass of petrified vegetable matter removed in clearing the portion of the 

 skeleton first described. Some of these detached bony plates still adhere to the caudal 

 vertebrae, and may be observed to decrease in size as they approach the end of the 

 tail (T. X, fig. 1, i, ?). From their form, which is elliptical or circular, and from the 



