Prof. H. G. Seeley on the Ornithosauriuii ± alois. 253 



as the prepubic bones of the Ornithiscliian skeleton. I have 

 already pointed out that they resemble the anterior pair of 

 ventral bones in the pelvis of a Crocodile ; and this identifica- 

 tion of the prepubic bones in the Ornithischia makes a further 

 approximation to the condition in the Crocodile, because they 

 are found in a type in which the pubis is less developed than 

 in the Ornithosauria. If there is a difficulty in adopting this 

 osteological reading' it does not arise from any differences in 

 form between the bones in question in Ornithosauria, Ornith- 

 ischia, and Crocodilia, but rather from the fact that the 

 anterior pubic process of Iguanodonts, as preserved, is always 

 thin and shows no articular facet at its extremity, while the 

 bone which I would attach there (fig. 15) has a stout shaft and 

 an expanded articular end, which was oblique and rough and 

 shown by one specimen in the British Museum to have had a 



Fis. 15. 



Restoration of Ventral Aspect of Pelvis of Iguanodon. 



cartilaginous surface. These dissimilar conditions of the 

 corresponding portions of the pubic and prepubic bones appear 

 to characterize Ornithosaurs ; so that, although unexpected in 

 Iguanodon, they are perhaps not so antagonistic to coadapta- 

 tion of the bones as might at first thought appear. This 

 Ann. & Mag. N. Hist. Ser. 6. Vol. vii. 18 



