Prof. H. G. Seeley on the Ormthosaurian Pelvis. 211 



elements and subsequently broken away ; but there is no 

 evidence of fracture. No specimen is known in which this 

 bone is blended with the pubis ; and it' such a specimen were 

 available, it would not prove that the bone in question is a 

 portion of the pubis, if other specimens showed it as a separate 

 ossification, Ornithosaurs are fossilized in every conceivable 

 position, yet it is rare for the bones of the skeleton to be broken, 

 and frequently almost every bone is in its natural connexion. 

 Yet these prepubic bones are nearly always a little displaced 

 from the other parts of the pelvis. I believe the condition of 

 the pubis in every known Ornithosaur in which it is imbedded 

 in stone warrants me in affirming that it gives no evidence of 

 fracture ; but there is in a few examples some evidence in 

 favour of articulation at its ventral end. I therefore conclude 

 that the prepubic bones may still be accepted as constituent 

 elements of the Ornithosaurian skeleton. The bone has not 

 been found in the order Oruithocheiroidea from the Cretaceous 

 beds of Europe or America ; and the supposed lateral position 

 which I suggested for it in 1864-70 was based on a small 

 pit on the anterior pubic border, which is inconclusive and 

 otherwise unsupported by evidence. Its position was different 

 in the Pterodactylia. Professor von Quenstedt, who enriched 

 his specimens with almost incredible manual labour, cleaned 

 away the matrix from the underside of the pelvis in his type 

 specimen of Cycnorhamphus suevicus. He then found on the 

 inner border of the pubic bone a short articular tubercle placed 

 towards the ilium. He supposes this part of the pelvis to be 

 displaced, and suggests that the tubercle gave attachment to 

 the fourth bone of the pelvis, which he compared to the 

 marsupial bone in Mammalia. This is the only fossil in 

 which an author has described and figured an articular facet 

 for the prepubic bone. I have seen that specimen and dis- 

 cussed the question with von Quenstedt, and can only say 

 that I am unable to accept the interpretation as quite satis- 

 factory, because it is unparalleled by any other example. 

 The specimen of Bhampkorhynchus Gemmingi figured by 

 Zittel also exposes the interior of the pelvis ; but there is no 

 indication of a tubercle for articulation with the prepubis. 

 The anterior margin of the pubis is rounded. The bone is 

 drawn by Zittel as though fractured ventrally at a point 

 where it obviously thickens ; and it seems to me probable 

 from this fact and other evidence of the pelvic structure in this 

 species given by von Meyi r that the ventral part of tlie pubis 

 is broken away. 



If the pubic bone wei-e bent and fractured as a condition of 

 fossilization, it might be expected in the different families of 



