﻿KIM ME RIDGE CLAY. 



83 



At present I shall not spend time in analysing the grounds of such view ; but, return- 

 ing to the avian comparison, I may remark that the number of free vertebras between the 

 sacrum and skull, in Iguanodon, is 24, of which 7 are cervical, 17 dorso-lumbar ; in 

 Megaloscmrus present evidence supports an estimate of 23 such free vertebrae allowing 7 

 to the neck ; in the parts of the skeleton of the same individual Hglaosatmis, in the British 

 Museum, 10 vertebrae in natural succession include the hinder cervicals and succeeding 

 dorsals, but the more or less complete vertebrae scattered in the same mass of matrix support 

 an estimate of the vertebral formula not less in number than in Iguanodon ; whilst, as such 

 vertebrae are shorter in proportion to their breadth than in either Iguanodon or Megalo- 

 saurus, there may have been more than 24 between the skull and sacrum. In Scelido- 

 saarus 16 dorso-lumbar vertebrae are shown in succession in the blocks of lias in which they 

 have been exposed, and 6 at least, if not 7 cervicals, are also evidenced in the same 

 instructive skeleton of one individual Dinosaur. 1 



The proportion of the skeleton of Cetiosaurus longus in the Oxford Museum and that 

 of the allied Dinosaur (Omosaurus armatus) in the British Museum demonstrate the absence 

 of anchylosis in the dorso-lumbar region of the spine, and of any of the modifications of 

 the hindmost vertebrae which, in Birds, add to the mechanical bracing of the trunk upon 

 the pelvis : they show no lengthened pleurapophyses, having free proximal articulations 

 to anterior sacral vertebrae ; but, on the contrary, as in Mammalian quadrupeds, the 

 lumbar ribs are short, coalesced with their vertebra, and project as straight out- 

 standing transverse processes, not opposing the lateral movements of the trunk upon the 

 pelvis, but, with the antecedent vertebrae, negativing the notion of any action of muscles, 

 proceeding from the pelvis and thigh-bones to grasp fast a trunk, and uplift it, together 

 with the fore-limbs, neck, and head, clear of the ground, as during the hypothetical 

 bipedal march and course of the huge dinosaurian Reptiles. 



The ascertained conformity of organisation in known Dinosauria supports the 

 conclusion that a long, bulky, bendible body stretched forward from the pelvis and hind 

 limbs throughout the order. 



In Birds the bony ' vertebral ' and ' sternal ' ribs of the few vertebrae of their short 

 dorsal region are spliced together by a mechanism of which no trace has hitherto been 

 discovered in the corresponding more lengthened region of the spine of Dinosauria ; there 

 is a like absence, in these cold-blooded vertebrates, of the anchylosis of centrums, and of 

 ossified tendons or neurapophysial splints — avian structures — which limit, to the essential 

 minimum, any movement between one prepelvic vertebra and another. Every modifica- 

 tion of the Bird's skeleton concurs to facilitate the carriage of the prone trunk, as one 

 compacted mass, upon the vertical pair of limbs, and not one of these modifications exists 

 in Reptiles recent or extinct. 



What, then, we next ask, were the arrangements in the neck to diminish the 



1 Palseont. vol. for 1860 (Scelidosaurus), p. 11, tab. i — vi. 



m 



