. The Ceratopsia. Ceratopsia. Fig. 38.—A, Superior view of left angular of type of Tricera- tops flabellatus, No. 1821, Yale Museum; B, inferior view of same, a, External border; ity; ss, surface for surangu- lar; sar, surface for articu- lar; sd, surface for dentary; es, exposed surface; sp, splenial surface. One-eighth natural size. THE ARTICULAR. Fig. 39.—A, External view of right surangular of type of Tricera- tops flabellatus, No. 1821, Yale Museum; B, internal view of same, a, Supero-anterior angle; sd, surface for dentary; mf, ex- ternal mandibular foramen; asq, artic
. The Ceratopsia. Ceratopsia. Fig. 38.—A, Superior view of left angular of type of Tricera- tops flabellatus, No. 1821, Yale Museum; B, inferior view of same, a, External border; ity; ss, surface for surangu- lar; sar, surface for articu- lar; sd, surface for dentary; es, exposed surface; sp, splenial surface. One-eighth natural size. THE ARTICULAR. Fig. 39.—A, External view of right surangular of type of Tricera- tops flabellatus, No. 1821, Yale Museum; B, internal view of same, a, Supero-anterior angle; sd, surface for dentary; mf, ex- ternal mandibular foramen; asq, articular surface for quadrate; sar,surface for articular;roa,mar- gin for contact with angular; sa, surface for contact with angular. One-eighth natural size. The articular is embraced below by the angular and surangular, while on its external side it is firmly lodged between the superior and inferior horizontal branches of the latter bone; together with these bones it entirely incloses posteriorly the mandibular fossa. It forms about three-fourths the articular surface for the quadrate and sends backward a triangular process which extends some 50 millimeters beyond the quadrate and is deeply excavated on its superior surface. The antero-internal margin of the articular is produced forward, especially along its superior border, where it forms a sharp process, trian- gular in cross section, which, when in position, is in contact with the splenial and the pos- terior internal angle of the den- tary. It forms the posterior and a portion of the superior border of the internal mandib- ular foramen. The manner in which the angular, surangular, and artic- ular interlock with one another is well shown in fig. 40, which represents all these bones in their normal position relative to one another. Although the bones of this region are short and small and are not coossified either with themselves or the dentary, except perhaps in very old individuals, }^et when adjusted to each other and t
Size: 1627px × 1535px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, bookpublisherwashingtongovtprin
