LIFE AND KINSHIP OF DINOSAURS. 609 



sprawling fore and hind limbs in running along, relates in Land-tortoises to a more 

 vertical position of the leg, and to the greater weight which the entire hind limb has to 

 sustain in the progression of those Reptiles. 



In Dinosaurs (woodcut, Fig. 12) the thigh (/), as well as the leg {tb), were probably less 

 obliquely disposed, in quadrupedal locomotion, than in any existing Reptiles, save, perhaps, 

 the Chameleons. The four or five sacruls, interlocked, as in Birds and Tortoises, by 

 alternating centrums and neural arches, have been recognised as physiologically related to 

 correspondingly developed hind-limbs and a concomitant carriage of their huge elongate 

 trunk, in a way approaching to that in the large gravigrade Mammals.* 



It is requisite, in the present test, to determine as nearly as may be the relative length 

 of the pre-pelvic part of the trunk to the pelvis in Dinosaurs. 



It may be presumed that those who represent the pubic-ischial elements of such 

 pelvis, as being disposed in the avian fashion, intend the inference that, so far, the 

 pelvis of the Dinosaurs related to the same bipedal mode of ])rogression as in Birds, 

 and that the trunk was similarly borne along, prone, upon the single pair of hind- 

 legs.f 



If, however, our knowledge of the dinosaurian pelvis being rectified, it should be 

 averred that the trunk of the Iguanodon or Megalosaur might be otherwise carried than 

 in Birds, that it was reared upright and so balanced, as in Man, upon a pair of hind, 

 or in that case lower limbs, it may then be necessary to enter upon a series of comparisons 

 between the dinosaurian and human skeletons in connection with such upright mode of 

 progression. 



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

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

 sacrum cmd skull, in Tyuanodun, is 24, of which 7 are cervical, 17 dorso-lumbar ; iu 

 Megalosaurus 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 Hglaosaurus, 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 

 vertebraj 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- 

 saurus IG dorso-lumbar vertebrae are shown in succession in the blocks of lias in which they 

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

 instructive skeleton of one individual Dinosaur. 



* 'Report on Brit. Foss. Reptiles,' 1841. 



f " Not a ground-crawler, like the alligator, but moving with free steps chiefly, if not solely, on the 

 hind limbs, and claiming a curious analogy, if not some degree of afiinity, with the ostrich." Phillips, 

 ' Geology of 0.xford,' p. 19G. Such an idea, if it ever 'suggested itself to my mind, was never expressed, 

 and must have been instantly dismissed through considerations akin to those detailed in the text. 



