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| Keywords: The Quarterly journal of the Geological Society of London (13937257252).jpg 394 PROF H G SEELET OX THE PELTIS OF ORNITHOPSIS <br> The suture with the ischium which is nearly straight may have <br> heen nearly vertical ; it is 30 centim long The sutural surface <br> becomes narrow as it descends and the bone becomes thin towards <br> the median line <br> The ischium is curved in length with the convexity on the inner <br> side and it is twisted at an angle of 45° so that the superior distal <br> surfaces are directed outward and upward and the inferior margins <br> converge and meet in a broad V shape This union is assisted by <br> the internal distal border of the bones being bevelled at an angle of <br> 45° for a length of 30 centim and this surface is marked with coarse <br> parallel longitudinal sutural lines Externally the distal extremity <br> of the bone is thickened superiorly for 15 centim as though for <br> muscular attachment The bone is imperfectly preserved so that <br> the larger part of the anterior sutural union with the pubis is broken <br> away towards the median line of the body At a distance of 43 <br> centim from the proximal end there is on the internal border a <br> small portion of smooth ossified margin which is concave and this I <br> take to indicate the posterior termination of the proximal expansion <br> of the bone Externally the infra-acetabular surface is concavely <br> excavated in the usual way The sutural surface for the ilium is <br> 15 centim long ; the acetabular interval between the ischium and <br> pubis is 15 centim wide and the iliac attachment on the pubis is <br> 19 centim long as preserved and appears originally to have mea- <br> sured about 33 centim The greatest thickness of the bone where <br> it unites with the ilium is 5 centimetres I am not aware that this <br> type of pelvis has hitherto been observed The antero-posterior <br> arch between the anterior symphysis of the pubic bones and the <br> posterior symphysis of the ischia is a well-marked characteristic <br> of Saurischian reptiles ; but it remains to be determined to what <br> extent the median union of the pubic bones is developed in the <br> group <br> From the imperfect fragment preserved it is impossible to judge <br> of the form of the ilium but it does not make any recognizable <br> approximation to the bone in those American genera which offer <br> the closest resemblance of form to the pubis and ischium <br> When the bones from the Oxford Clay are compared with those <br> from the Wealden of the Isle of Wight there are several minor <br> differences of proportion ; but although the internal border of the <br> Wealden pubis is badly preserved its distal inner border shows an <br> inclined symphysial suture and a symphysial suture is present on the <br> most convex part of the arch in the middle of the bone which is <br> more prominent than in the relatively wider thicker bone of <br> Ornithopsis Leedsii In the Wealden specimen the obturator foramen <br> in the pubis is relatively nearly twice as large as in the Oxford-clay <br> specimen and is more obliquely placed The ischium in the <br> Wealden specimen is relatively much broader and stronger than in <br> the Oxford-clay fossil ; it has a much wider iliac head defined <br> by a deep concave subacetabular notch which is almost wanting in <br> the other type; the distal end is expanded and though its symphysis 36940213 113696 51125 Page 392 Text 45 http //www biodiversitylibrary org/page/36940213 1889 Geological Society of London NameFound Ornithopsis NameConfirmed Ornithopsis NameBankID 4270321 NameFound Peltis NameConfirmed Peltis EOLID 3486400 NameBankID 4287422 Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 45 1889 Geology Periodicals Smithsonian Libraries bhl page 36940213 dc identifier http //biodiversitylibrary org/page/36940213 smithsonian libraries Information field Flickr posted date ISOdate 2014-04-21 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/13937257252 2015-08-26 05 54 46 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1889 Photos uploaded from Flickr by Fæ using a script | ||||
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