On the anomodont Reptilia and their allies / by H.G. Seeley.

  • Seeley, H. G. (Harry Govier), 1839-1909.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: On the anomodont Reptilia and their allies / 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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    show one foramen without indicating the other. There is no reason to suppose that all Anoinodonts have a radial as well as an ulnar foramen, for the external foramen is certainly absent in Galesaurus ; but, when only one foramen is seen, its direction appears to be transverse, and it passes obliquely from the ulnar to the radial side. On referring to drawings which I made in the Senckenberg Museum, at Ffankfort-on- the-Main, in 1878, of some fragments of humeri which were described by VON Meyer, and have since been regarded as European Theriodonts by Sir R. Owen, I find both foramina present, though the radia] foramen is relatively small in Brithopus. The ecto-pterygoid bone is stated by Sir R. Owen to cease to exist in both Theriodonts and Dicynodonts; and this bone never reappears in the Mammalian series. But two specimens in the British Museum suggest doubt whether the bone is absent, or hidden by the pterygoid. Sir R. Owen also finds in Iguanodon, Scelidosaurus, and Pareiasaurus dental characters which reappear in certain Mammalia, such as the Sloth and Kangaroo. He finds the number of incisors in these fossil Reptiles to be closely comparable with Marsupials. Thus, Bidtlpliis and _ 5 _ 5 Cynodraco have the formula i ; and in it is ^ 3T3 ' Thylacinus, Sarcophilus, and Cynochamjjsa This memoir was succeeded by two papers' upon PIatyp>odosaiirus rohustus. The vertebrae are said to differ from those of Kistecep>hcdus and Anthodon in the less depth of the terminal concavities, in which character they approach Dicynodon and Ouden- odon; but among the Plesiosauria this character is very variable, and seems to me a specific rather than a generic difference. The author compares tliis vertebral condi- tion to that found in Echidna, but I do not find the resemblance close enough for comparison. An element of the sternum is recognized as the foremost sterneber, and identified with the first sternal element in Ornithorhynchus and the sternum of modern Lizards ; and this bone is inferred to have been one of a series such as is present in Chameleons and ISkinks. Its upper border is thought to have joined the coracoid, as in Monotremes, while its lower border may have given attachment to sternal ribs. The scapula is intermediate between that attributed to Dicynodon and the scapula of Kistecephalns. The nearest resemblance to the humerus is found in OrnithorJiynchus and Echidna. On the digits it is remarked that the ungual phalanges, though relatively shorter, have more the proportions of those of Echidna than of Ornithorhynchus. What remains of the femur is compared with the proximal part of the bone in Echidna. The sacrum is said to be more Mammalian than that of Dicynodon, and to come nearer in shape to the Megatherioid Mammals. The Llammalian cliaracter is considered to be marked by the breadth of the iliac bones, and the extent of the confluence of the similarly expanded ischia and pubes, and by their confluence at the ischio-pubic symphysis. * ‘ GeoL Soc. Quart. Journ.,’ vol. 36, p. 414, 1880; aiid vol. 37, p. 266, 1881.