. Annals of the Carnegie Museum. Carnegie Museum; Carnegie Museum of Natural History; Natural history. Wieland : Plastron ok the Protostegin^e. <) Dermochelys amongst existing, and amongst extinct forms, only in the several genera of the Thalassemydidae of the European Jurassic and Cretaceous, together with Protosphargis of the scaly clays of Italy. The epiplastron of Archelon as represented in superior view in Fig. i is of subcrescentic outline with the anterior limb heavy, and the posterior broadened, flattened, and digitate. The thickness of the heavy anterior end is centimeters, and
. Annals of the Carnegie Museum. Carnegie Museum; Carnegie Museum of Natural History; Natural history. Wieland : Plastron ok the Protostegin^e. <) Dermochelys amongst existing, and amongst extinct forms, only in the several genera of the Thalassemydidae of the European Jurassic and Cretaceous, together with Protosphargis of the scaly clays of Italy. The epiplastron of Archelon as represented in superior view in Fig. i is of subcrescentic outline with the anterior limb heavy, and the posterior broadened, flattened, and digitate. The thickness of the heavy anterior end is centimeters, and an accompanying humerus is exactly 2 feet in length. As in the Trionychydae there is no true sutural union with the ento- plastron, the contour showing that the superior face of the epiplastron was overlain by the antero-external border of the entoplastron. Be- yond this border the anterior limb of the epiplastron projected about 7 cm. like a broad, short, heavy horn, with its convex sideental. Four. Fig. 2. Aspidonectes spinifer. Nether (ectal) view of plastron. X i« ep, epiplastron ; en, entoplastron ; /, /, anterior and mesial foramina. ( Cf. epiplastron of Archelon and Dermochelys, also of Thalassemydidae.) broad, shallow furrows increasing in depth from the inner to the outer side, mark the contact of as many overlying digitations or ridges which may all have been entoplastral, rather than in part hyoplastral. This lack of sutural union and the boomerang-like shape of the epi- plastron show how it must have been the very first bone to be torn out. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Carnegie Museum; Carnegie Museum of Natural History. [Pittsburgh] : Published by authority of the Board of Trustees of the Carnegie Institute
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectnatural, bookyear1901
