The characters of Pteranodon / by G.F. Eaton.

  • Eaton, George Francis, 1872-1949.
Date:
1903
Catalogue details

Licence: In copyright

Credit: The characters of Pteranodon / by G.F. Eaton. 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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    the avian sacrum, chose the intervertebral foramina as the best criteria for distinguishiniJ^ tnie sacrals from sacro-dorsals and uro-sacrals. In the present fossil specimen there are, of course, no nerves to serve as guides, but I hope to show in a subsequent pa]:>er that vertebrae 5, 6, and 7, whicli clearly form a natural division, are tlie true sacrals. Vertebra 4 may prove to be the homologne of the last lumbar vertebra in the sacrum of recent birds. In closing I should like to state, with due apologies to Prof. Lydekker, that the “parallel” between the sacrum of Pteranodon and that of recent birds is striking, though I have no desire to postulate “ converging lines ” of structure and descent. Paleontological Laboratory, Yale University Museum, June 8, 1903. EXPLANATION OF PLATES. Platk VI. Figure 1.—Restoration of skull of Pteranodon. True outline of sagittal crest is shown by continuous line. Marsh’s restoration of sagittal crest is sho^vn by dotted line. One-sixth natural size. Figure 2.—Enlargement of Williston’s'diagram of skull of Pteranodon. Approximately one-quarter natural size: Plate VII. Figure 1.—Pelvis of Pteranodon', side view. Figure 2.— “ “ ; top view. Figure 3.— “ “ ; bottom view. All three figures are one-half natural size.