LIASSIC DINOSAURS. 103 



I infer, therefore, from the size and proportions of the two vertebras just 

 described that they correspond with the sixth aiid seventh in the Crocodile, and 

 that the Scelidosaurus, with probably other Dinosauria, differed from Crocodilia 

 and from most Lacertilia in the long and slender form of most, if not all, of the 

 cervical ribs ; but that these manifested their more essential Crocodilian affinity in 

 their twofold articulation, by a bifurcate head, with distinct upper ( d ) and lower 

 ip) transverse processes. 



The fourth block included, with the scapular arch, ten of the anterior dorsal 

 vertebrae (Pis. 49, 50). The hinder fracture of the block has detached the anterior 

 articular surface from the eleventh dorsal, the rest of which is the first of the series 

 of the five following dorsals in the fifth block of Lias (PI. 52, figs. 1 and 2). The 

 hinder fracture of this block has pretty equally bisected the last vertebra, which 

 bears free ribs, viz. the sixteenth dorsal, the hinder half of which remains in the 

 fore part of the block (PL 53), including the lumbar and sacral series of vertebrse. 

 The section of the eleventh dorsal thus exposed near the anterior articular surface 

 of the centrum is represented of the natural size in PI. 52, fig. 1, d ii. That 

 through the middle of the sixteenth dorsal vertebra is similarly represented in 

 fig. 2, D 16. 



The spinous process of the first dorsal vertebra (PL 45, D i) is 1^ inch in height 

 and 8 lines in fore-and-aft extent ; the spine increases in both directions to the 

 fifth of these vertebra3 ( 5 ), which is 2 inches 4 lines in height and 1 inch 10 lines 

 in basal extent. The spines continue of about the same height to the tenth vertebra, 

 D 10, with summits obtusely rounded, almost truncate. In the eleventh to the 

 sixteenth dorsals, PL 51, d ii — d 16, the spines acquire their greatest fore-and-aft 

 extent, with truncate summits, but no increase of height. Although these spines in 

 the last six vertebras are nearly 2| inches in antero-posterior extent, their summits 

 do not come into contact, but leave interspaces of from 5 lines to 8 lines. 



The prezygapophyses in the anterior dorsal vertebras look inward and a little 

 upward, the postzygapophyses in the reverse directions, but as the vertebrjB recede 

 in position the aspect of the surfaces becomes more nearly horizontal (PL 52, fig. 1 z). 

 The diapophyses are subdepressed, 10 lines in breadth in the second vertebra, and 

 gradually increasing to a terminal breadth of 15 lines in the ninth and tenth 

 dorsals (PL 49, d, d). The parapophyses, as in the Crocodile, gradually pass from the 

 centrum to the neural arch, and are seen at^, fig. 1, PL 51, upon the under and fore 

 part of the diapophysis (d) in the eleventh of this series of dorsals, where the length 

 of the diapophysis from the base of the neural spine is 2 inches 9 lines. No trace 

 of parapophysis, or of the "head" of the rib, remains in the last three dorsals; 

 the diapophysis is entire, as at d, fig. 2, PL 51. 



The ribs of the twelve anterior dorsal vertebra show both the head and the 

 tubercle, the neck becoming gradually shorter in the last three. In the seventh 



