LIASSIC DINOSAURS. 90 



reptilian provision for successional teetli in reserve alveoli, containing tooth- 

 germs, at the inner side of the base of the teeth in place (PI. 46, fig. 2, c). 

 The teeth gradually increase in size from the hindmost to the fifth in advance, 

 continue of about the same size to the tenth, and then gradually decrease in size 

 to fractured fore part of the jaw. 



Were the serrated borders of the terminal half of the crown to be worn down, 

 the teeth of Scelidosmtrus would be like those referred to Eylmosaurus in Vol. i, 

 p. 377, Vol. ii, PI. 39. There is no evidence, however, that any of them have 

 been so worn down ; in this respect they resemble more the teeth of Echinodon, 

 the upper teeth in Scelldosaurus differing chiefly in the proportions of length to 

 breadth of the crown. Whether the anterior teeth had the simple laniariform 

 character at the fore part of the jaws in Scelldosaurus, as in Iguanodon and 

 Echinodon, remains to be proved. The finely and sharply serrated and pointed 

 teeth of the Scelidosaurus glided upon each other, the upper on the outer side 

 of the under, like the blade-shaped crowns of the carnassials of feline mammals ; 

 and yet the similarity of the teeth, in their number and uniformly small size, 

 to those of the modern Iguanas suggests that they may have been put to like 

 uses. The compressed, serrate crowns in those herbivorous lizards worked 

 obliquely upon each other, in a similar scissor-blade way. In Iguanodon the 

 dentition is obviously modified more decidedly for mastication of vegetable 

 substances. In Scelidosaurm it is adapted for division of such substances, but 

 it would be equally efi'ective in piercing and cutting or tearing through animal 

 textures. 



If this Dinosaur occasionally went to sea in quest of food, it may be expected 

 to present in the fore part of the jaws, wanting in the present specimen, 

 laniariform teeth, as in Iguanodon (PI. 49, fig. 9, i), for the prehension and 

 retention of living prey. Should these prove to be absent, and the dental series 

 to begin as it ends, it will incline the balance of probability to the phytophao-ous 

 nature of the Liassic Scelidosaurus. 



Following in the track opened out by the discovery of the skull, about twelve 

 successive blocks of Lias were secured, with more or less evident indications of 

 included bones, all of which, together with the skull, were secured and transmitted 

 to the British Museum. Subsequent complete exposure of the included organic 

 remains has brought to light the entire vertebral column of the trunk and tail, to 

 very near the termination of the latter ; the scapulo-coracoid arch and part of one 

 fore Hmb being associated with the thorax, and the iliac bones and both hind 

 limbs with the sacrum : all were parts of the same individual Dinosaur. 



In the operation of clearing off the matrix, scattered dermal bones first presented 

 themselves, and these were removed, with a note of their position, when it became 

 plain that they did not touch or rest upon any part of the endo-skeleton. This 



