J. B. Hatcher — Two New Ceratopsia. 415 



acutely pointed and regularly triangular' in cross-section. The 

 infratemporal arch, as in T. serratus, is formed by the quad- 

 rate with overlapping processes from the jugal and squamosal, 

 that from the latter element occupying a slightly more ele- 

 vated position in the type of the present species than in that 

 of T. serratus. The exoccipital process extends distally 

 beyond the quadrate and projects as a small angular process. 

 There are six exoccipitals, borne wholly on the squamosal, and 

 at least three more between the last of these and the single 

 median one situated at the median parietal region. Though 

 the frill is not sufficiently perfect in this region to determine 

 the number of epoccipitals with accuracy, there cannot be 

 fewer than nineteen. The postfrontal fontanelle is large and 

 circular in outline. The median longitudinal crest of the parie- 

 tals is well defined and bears the usual rugosities. Near the 

 apex the right horn core has been worn into a peculiar form 

 by the action of wind, sand and water while it protruded from 

 the sandstone concretion in which it was found prior to its dis- 

 covery. The palatial view shows no characters essentially dif- 

 ferent from those of other species of this genus. In the region 

 of the supraoccipitals and parietals the sutures are so obliter- 

 ated by age and obscured by distortion and crushing that it is 

 quite impossible to determine their nature. 



The Loiver Jaw. — The lower jaws with the predentary were 

 in position and in a splendid state of preservation. The pre- 

 dentary is rather longer than is common. On the superior 

 surface of the mandibular fossa near the anterior end two large 

 foramina pierce the wall and pass upward toward the dental 

 chamber. The splenial is very broad posteriorly and entirely 

 encloses the mandibular fossa, except at the opening of the 

 internal mandibular foramen. The coronoid process is low 

 and stout and superiorly it is produced forward into a broad 

 and somewhat decurved projection. At its greatest expansion 

 the superior border of the splenial covers over for a short dis- 

 tance the series of dental foramina on the inner side of the 

 dentary. The principal characters of the skull are well shown 

 in Plate XII, figures 1 and 2. 



The Vertebrce. — The vertebrae will be fully described in 

 that portion of the monograph relating to the osteology of the 

 genus Trieeratojps. 



Principal Measurements of Ty}ie of T. brevicornus (No. 1834-, 



Y. M.). 



Greatest length of skull 1652 mm 



Greatest breadth of frill _ 1120 



Expanse of jugal „ 600 



