File:Bulletin - United States National Museum (1920) (20479576866).jpg

Title: Bulletin - United States National Museum
Identifier: bulletinunitedst1101920unitfo (find matches)
Year: 1877 (1870s)
Authors: United States National Museum; Smithsonian Institution; United States. Dept. of the Interior
Subjects: Science
Publisher: Washington : Smithsonian Institution Press, (etc. ); for sale by the Supt. of Docs. , U. S. Govt Print. Off.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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OSTEOLOGY OF CARNIVOROUS DINOSAURS. 17 posterior end it sends out a vertically expanded branch that extends backward and outward and laps along the median anterior sui-faee of the opisthotic (fio;. 6). The prootic is bounded superiorly bj^ the parietal, anteriorly by the alisphenoid (orbitos- phenoid of Osborn) and inferiorly by the basisphenoid. Laclu-ymal (la.).—The elements bomiding the orbits anteriorly and uniting with the jugals and maxillaries below, and with the nasals and frontals above are here designated as the lachrymals. Osborn in his description of the Tyrannosaurus skull ' following Gaupp, called the same bones the adlachrymals, but which corre- spond to tlie lachrymals of most authors. Since the appearance of that work, Gregory - has conclusively shewn that paleontological evidence does not support Gaupp's views and reaches the conclusion that "the prefrontal of reptdes is not homologous with tlie lachrymal of mammals."
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Fig. S.—Left lachrymal of Antkodemus valens Leidy. Cat. No. 4734, U.S.N.M. i n.^t. size. A, external view; B, INTERNAL VIEW, j, END THAT ARTICULATES WITH THE JUGAL; mi, PROCESS THAT UNITES WITH SUPERIOR AND POSTERIORLY DIRECTED PROCESS OF MAXILLARY"; 7ia, BORDER THAT MEETS THE NASALS. The lachrymal in Antrodemus is an unusually robust element, the superior border of which forms a sharp, elongated (antero-posteriorly) elevation on the lateral median borders of the articulated skull. It may have supported, as first suggested by Osborn,' "something in the nature of a low dermal horn." The roughened surfaces of this portion of the lachrymal (fig. 8) are all indicative of the above conclusion. On the external side (fig. 8, A), below the area described above, the bone is excavated, and still further lightened by deep connecting chambers within the heavier part of the bone. The entrance to this chambered region is by two oval openings, the larger one being posterior. There is a slender tapering process which extends forward from the hornlike part of the prefrontal which meets the superior process from the maxillary, being 1 Mem. Amer. Mus. Nat. Hist., vol. 1, new ser., pt. 1, 1912, p. 7. » Journ. Morphol., vol. 24, March, 1913, pp. 3-!; Proc. Paleontol. Soc, vol. 24, June, 1913, pp. i41-242. 3 BuU. Amer. Mus. Nat. Hist., vol. 19,1903, p. 701. ^

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