ROOM III. REGXOSAURUS NORTHAMPTON!. 333 



in its antero-posterior diameter, and divided by a longitudinal 

 depression, whose termination obscurely indicates the position 

 of the hsemapophysial articulations ; but it must be remarked 

 that no unequivocal surfaces for the attachment of the chevron- 

 bone are apparent. 



The neural arch is large, and anchylosed to the anterior 

 half of the upper surface of the centrum, the posterior part of 

 which is left free. The anterior zygapophyses project directly 

 forwards, and advance over the exposed part of the body of 

 the contiguous vertebrae, and articulate with the depressions 

 on each side the spinous process. The transverse processes 

 are very strong and short, and project at nearly right angles 

 from the body. The spinous process is short and thick. 



These four vertebrae are placed on the shelf in a consecutive 

 line, but it is doubtful whether the two right hand bones are 

 in their natural order ; it seems probable that there was an 

 intermediate vertebra between the second and third, and be- 

 tween the third and fourth, so that two more would be re- 

 quired to complete the series. 1 



The chevron-bone found in the same block, and suspended 

 above the vertebras, 2 is obviously too small for articulation 

 with either of the above ; it is, however, important, as showing 

 the crocodilian modification of the process, if this bone belonged 

 to the same species of reptile ; but that is doubtful, for chev- 

 ron-bones found with similar vertebrae in the Isle of "Wight, 

 have the head confluent, as in the corresponding element of 

 the Iguanodon. 3 



REGNOSAURUS NORTHAMPTONI. Wall-case C. A portion 

 of the right side of the lower jaw of a lacertian reptile, placed 

 on the narrow front shelf in this case (see ante, p. 227), although 

 a mere fragment, and destitute of the crowns of the teeth, is 

 highly interesting, because it unequivocally indicates a genus 



1 See figures and descriptions of these fossils in " Phil. Trans.," 

 1850, p. 381, PI. XXII. XXIV. XXV. 



2 Ibid. PL XXII. fig. 8. 



3 Cetiosaurus. Professor Owen ascribes a few other vertebrae from 

 the "VVealden, which are deposited in this case, to the genus Cetiosau- 

 rus ; but as no bones of the extremities of strictly aquatic saurians 

 have been found in the strata of the Wealden, it appears more pro- 

 bable that these remains of the spinal column are referable to other 

 genera. 



