. The Ceratopsia. Ceratopsia. 130 THE CEEATOPSIA. offensive and defensive weapons. The form and character of the rostral bone are well shown in fig. 109. The predentary, fig. 110, is longer and more slender than the rostral. It is pointed anteri- orly and posteriorly and is triradiate, presenting two superior lateral processes which overlap the antero-superior margins of the dentaries and a single inferior median process which is bifurcated distally and passes beneath the antero-inferior borders of the dentaries. The dentary is short and shows a number of large and small foramina arranged in a
. The Ceratopsia. Ceratopsia. 130 THE CEEATOPSIA. offensive and defensive weapons. The form and character of the rostral bone are well shown in fig. 109. The predentary, fig. 110, is longer and more slender than the rostral. It is pointed anteri- orly and posteriorly and is triradiate, presenting two superior lateral processes which overlap the antero-superior margins of the dentaries and a single inferior median process which is bifurcated distally and passes beneath the antero-inferior borders of the dentaries. The dentary is short and shows a number of large and small foramina arranged in a some- what irregular longitudinal series on the external surface of the bone, as shown in fig. 41, mid- way between the inferior and alveolar borders and commencing just in advance of the base of the coronoid process. Between the base of the coronoid process and the anterior extremity of the dentary the external surface is deeply concave antero-posteriorly instead of nearly straight, as in some of the larger forms. The coronoid process curves strongly outward at the base. It is rather slender, of moderate height, and much expanded antero-posteriorly at the summit. The articular, angular, and surangular, fig. 40, are closely applied to and interlocked with one another in a somewhat complicated manner. They are not, even in the present specimen, which represents a rather old individual, coossified either with the dentary or with one another. The free condition of these elements, taken in connection with the open symphysis and the free quadrate and shallow articular cup, might be taken as indicative at least of the possibility of some lateral and fore-and-aft motion in the lower jaws. However this may have been, it is quite certain that the jaws were not absolutely rigid, though the manner in which wear has. 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
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Keywords: ., bookcentury1900, bookdecade1900, bookpublisherwashingtongovtprin
