SACRUM OF THE IGUANODON. 319 



column ; whereas in all living saurians the sacrum 

 consists of but two vertebrae. The neural arches 

 of the vertebrae are shifted to the interspaces be- 

 tween the bodies of those bones, by which more 

 solidity is given to the pelvic arch. Professor 

 Owen (who first pointed out these modifications of 

 structure) states, that the sacrum of the Ostrich 

 presents the same characters, and in the young 

 bird the individual vertebrae, and the remarkable 

 change in the relative position of the vertebral 

 elements, may be clearly traced. 



Though these details are of the greatest interest 

 to the comparative anatomist, I should not have 

 dwelt upon them in the present work, were it not 

 probable that specimens of this part of the ske- 

 leton will come under the notice of the visitor, and 

 would, perhaps, from their unsightliness, be re- 

 jected. I have obtained from Brook Bay several 

 waterworn portions of the sacrum, consisting of 

 two or three anchylosed vertebrae; the finest ex- 

 ample of the entire series belonging to a large 

 individual, was found on this coast.* 



Form of the Iguanodon. — From the numerous 

 detached bones that have been collected from 



* This fossil is in the interesting museum of W. D. Saull, Esq., of 15, 

 Aldersgate Street, City, to which visitors are, with great liberality, admitted 

 every Thursday at 12. Mr. Saull's collection of organic remains contains 

 many specimens from the Isle of Wight. 



