. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Prof. H. G. Seeley on the Ornithosaurian Pelvis. 245 Cycnorhamphus Fraasii. In the drawing, which I copy from my note-book, it is manifest that the pubis and ischium are closely comparable with the same bones in {Pterodactylus) dubius, except that a thin osseous plate extends backward from the anterior thicker part of the pubis, so as to fill in much of the deep notch which in Pt. dubius appears to divide the pubic and ischiac bones, and which would otherwise be seen in Cycnor
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. Prof. H. G. Seeley on the Ornithosaurian Pelvis. 245 Cycnorhamphus Fraasii. In the drawing, which I copy from my note-book, it is manifest that the pubis and ischium are closely comparable with the same bones in {Pterodactylus) dubius, except that a thin osseous plate extends backward from the anterior thicker part of the pubis, so as to fill in much of the deep notch which in Pt. dubius appears to divide the pubic and ischiac bones, and which would otherwise be seen in Cycnorhamphus Fraasii. It will also be seen that the ventral border of the ischium is straight, and I suggest that these straight borders not improbably met in a median sym- physis. Still they are not thickened at the ventral border, as is usual in a median union; but then there is a like condition in Crocodiles in the borders of the ischia which are in median contact. If the ischia converged ventrally at all, the narrow posterior width of the sacrum shows that they must have had a median union. The shortness of the pubis similarly shows that no median union of the ventral margins of those bones could take place. But if the thickened anterior ventral end of the pubis is compared with the stalk of the prepubic bone, a suggestive correspondence in size of the two parts is seen j and I regard the two bones as having been in articular con- tact, so that the prepubic bones made an anterior median ventral symphysis corresponding to that usually made by the pubes. This interpretation is not easily harmonized with that offered by Quenstedt without adopting his hypothesis of displacement of the pubis in Cycnorhamphus suevicus, always supposing that the tubercle to which he believes the prepubic bone to have been attached really carried that element in the skeleton. The value of evidence in this matter of the nature of the prepubic bone depends partly on its cumulative character. I therefore t
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