120 BRITISH FOSSIL REPTILES. 



centrums, almost touching the posterior half of the twenty- seventh and the 

 contiguous two thirds of the twenty-eighth caudal vertebra ; obliterating an 

 interspace which should have been occupied by muscle, tendon, ligament, and 

 other soft parts in the recent animal. 



The dermo-h^emal spine below the twenty-fifth and twenty-sixth caudals 

 differed only in its larger size from the succeeding one. Part of the base of the 

 corresponding dermo-neural was preserved. 



In the series of nine consecutive caudal vertebra (PI. 56, fig. 1), the number 

 and disposition of the dermo-neural and dermo-h^mal bones were more fully and 

 satisfactorily exhibited. Three consecutive dermo-neurals extended over a series 

 of seven vertebrae, from near the fore part of the first to near the hinder half 

 of the last of these seven, each extending over the interspaces of two vertebrce. 

 The corresponding dermo-h^mals are of smaller size, cross only one intervertebral 

 space, which is the second or posterior of those so crossed above, and their 

 hinder end is a little further back than that end of their homotype above. But, 

 in working out these vertebriB, indications of a third series of caudal dermal bones 

 were first met with. There extended over the articulation between the twenty- 

 first and twenty-second caudals the base of a dermal bone, 3 inches long, crushed, 

 with its apical ridge broken off. On its removal, the vertebrae it crossed were 

 seen to have been displaced to the extent of nearly an inch. The position of this 

 bone, and the ascertained relations of the neural and hfemal dermal bones to their 

 vertebrae, made it improbable that it was one of either of these series displaced ; 

 and attention was quickened, which led to the detection of a similar appearance 

 further in advance, to be presently described. 



The best preserved dermo-neural, in the series of nine caudal vertebrae (PL 56, 

 fig. 1, dn), presents a basal longitudinal extent of 3 inches 5 lines, with a basal 

 breadth of 1 inch 9 lines ; its quasi worm-eaten, rugose sides, converge to an 

 upper margin, not quite entire, but with apparently a contour resembling the 

 dermo-neural in fig. 5. The present larger bone overlies the twentieth and 

 contiguous portions of the nineteenth and twenty-first caudal vertebrae. The 

 corresponding dermo-haemal bone {d, Ji), with a longitudinal basal extent of 

 2 inches 6 lines, and a basal breadth of 1 inch 3 lines, underlies the twentieth 

 and twenty-first caudals, extending along a greater proportion of the former. 

 Its sides, similarly but more finely sculjjtured than the dermo-neural above, 

 converge to a convex inferior border ; the depth of the side being not less than 

 1 inch 6 lines. The next dermo-neural in advance overlies the eighteenth and 

 contiguous half of the seventeenth caudal vertebrae. It presents a basal extent 

 of 3 inches 6 lines, with a basal breadth of 1 inch 6 lines. The base of the 

 corresponding dermo-htemal spine is preserved, which underlaps the hinder two 

 thirds of the eighteenth and the front third of the nineteenth caudal. Its base is 



