On the bone in Crocodilia which is commonly regarded as the os pubis, and its representative among the extinct Reptilia / by H.G. Seeley.

Harry Govier Seeley

Date:: 1887

Credit: On the bone in Crocodilia which is commonly regarded as the os pubis, and its representative among the extinct Reptilia / by H.G. Seeley. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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$pnbis were not developed, the homology would be supported by a similar plan of pelvic construction. Finally, there is some evidence that a similar structure is developed in the abdominal region of the allies of Iguanodon, without being in direct union with the pelvis. As long since as 1841 Dr. Mantell, F.R.S., figured in the ‘Philosophical Transactions’ (PI. 8, fig. 2) an undetermined Wealden bone, which is now in the British Museum, registered as No. 2218. It is not quite perfect, but is sug- gestively similar to the pre-pubic bones of Ornithosaurs. A thick sutural surface shows that it met a similar bone in the median line. Subsequently Mr. S. H. Beckles, F.R.S., obtained another specimen into which two such bones entered as constituents, which was exhi- bited during the British Association Meeting at Brighton, in 1872, and nltimately described and figured by Mr. J. W. Hulke, F.R.S.* Bones, like that figured by Mantell, have long been in the British Museum. And Professor Cope has figured a pair of similar bones in Piclonius mirabilis.f Mr. Hulke interpreted Mr. Beckles’ specimen as consisting of the clavicles and interclavicle. Mr. W. Davies, F.G.S., had interpreted the isolated bones like Mantell’s No. 2218, as clavicles, and his determination had been accepted by Professor 0. C. Marsh; so that until M. Dollo regarded them as parts of the sternum they had been regarded as clavicles. Dr. George Baur, of Tale College, sub- sequently in 1885'j' suggested that the supposed sternal apparatus of Iguanodon should be turned round, so that the supposed clavicles would become posterior processes of the sternum, and this view has been supported by Cope and adopted by myself. I suppose that the interpretation of the Beckles specimen was a consequence of its con- dition of preservation, by which fractures came to simulate sutures. Those fractures which are assumed to limit the clavicles, so as to allow the supposed interclavicle to extend between them, follow very different courses from the natural limits of the bones. If Mantell’ fossil already referred to is superimposed upon Mr. Beckles’ spe- cimen, then it is manifest that the broad part of the specimen is made up of two such bones which meet by median suture, and extend for two-thirds the length of the specimen. Some trace of the trans- verse suture may perhaps be seen which separates these bones from a thin ossification which extends beyond them. Hence there can be no interclavicle between the supposed clavicles ; and the evidence for the identification of the clavicles disappears. Turning the specimen so that the supposed clavicles point posteriorly, they will be found to make a remarkable approximation in form to the pre-pubic. * ‘ Geol. Soc. Quart. Journ.,’ vol. 41, 1885, PI. XIV, p. 473. t ‘ American Naturalist,’ Feb. 1886, p. 154. + ‘ Zoologisclier Anreiger,’ No. 205, p. 561.$