LOWER LIAS. 25 



with a slight concavity to the upper ridge, which has been broken off in each, so 

 that its height is conjectural. Other evidences of dermal bones on the under part 

 of this slab are too fragmentary and scattered to throw any light upon their natural 

 arrangement. On the right side (Tab. II), overlying the ends of the ribs, about 

 ten inches distant from the vertebrae, are preserved three of a series of flattened, 

 sub-ovate, dermal scutes {da, da), about 3 inches by 2 inches in the long and cross 

 diameters, and from 2 to 4 lines in thickness. The outer surface exhibits the 

 same character of sculpturing as do the dermal bones of the tail ; the inner surface 

 is smooth. 



In the block containing the second and third cervical vertebras the pair of 

 lateral, unsymmetrical, dermal bones have been preserved nearly in their natural 

 position. They are three-sided ; the shortest is directed towards the intervening 

 vertebras; the side next in length looks downward; the outer surface, directed 

 upward and outward, is the most extensive. These scutes have been fractured 

 through their centre. They show an external, very compact, layer of bone, 

 thickest on the outer or peripheral side. The rest of the bone shows a rather 

 close cancellous structure. Above these, but slightly displaced, is a pair of wedge- 

 shaped bones, which are probably dermo-neurals, indicative of a parial arrange- 

 ment of these along the nape, contrasting with their single series above the tail- 

 Each of these dermal bones are somewhat unsymmetrical in form, 2 inches 9 lines 

 in the length of the base, 1 inch 9 lines in breadth, with the median surface more 

 extensive than the outer, and both converging to a ridged summit, but which is 

 broken away. 



The anterior pair of nuchal scutes is preserved in connection with the occiput, 

 overlapping the atlas (Tab. I, fig. 1, dn, »•)• They are similar in shape, but smaller 

 in dimensions, than those last described, and have been broken across. 



From the sum of the foregoing observations, it may be inferred that the surface 

 of the Scelidosaur was defended by several longitudinal series of massive dermal 

 bones, those occupying the median and upper surface being arranged in pairs upon 

 the nape and singly along the tail. External to these were a lateral series, at least 

 two in number but probably more, on each side the trunk, having the same wedged 

 and ridged shape as the dermo-neurals. Beneath these were flattened, ovate scutes 

 along the lower lateral part of the thoracic-abdominal region. In the tail we have 

 more decisive evidence of a single median row of large, symmetrical, cuneiform, 

 hollow-based, superiorly ridged dermo-neurals, with dimensions making three 

 occupy the space of five vertebras along the base of the tail, and nearly seven 

 vertebras along the hinder half of the tail. There was a corresponding median 

 series of smaller and less vertically extended dermo-hasmal bones, and also a single 

 series of dermo-laterals, of more depressed and fuller ovate form, on each side. 



The accidents attending the decomposition of the carcass of this reptile seem 



4 



