LIASSIC DINOSAURS. 123 



between the spines of tte second and third dorsals, and another between those of the 

 fourth and fifth dorsals (PI. 49, dn, dn). On the left side of the thorax (PL 50) 

 are preserved some of the upper lateral series of dermal bones {dnl), showing 

 their natural position and intervals. On the same side, beneath the fore- 

 going (PL 50, d l), are some larger wedge-shaped dermal bones. Three of 

 these may have been displaced from above the neural spines. They are 

 elliptical, 3 inches long, 2 inches broad at the base, with the sides converging 

 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 (PL 49), 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 vertebrne the pair of 

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

 position. They are three-sided ; the shortest is dii-ected mesiad ; the side next in 

 length looks downward ; the outer surface, more convex, is directed upward and 

 outward, and 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 arrangement 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 (PL 48, fig. 1, dn, r ). 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-neiu-als. 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, 



