1S92.] ^43 ■ [Cope. 



foramina, one above the other, the inferior issuing in a deep groove or 

 fossa. They are bounded externally by a broad vertical ala. Anterior to 

 this ala are two other large foramina, one above the other, both issuing 

 from fosste. One or both of these is the trigeminal. The middle line of 

 the brain case is keeled below, except near and at the anterior extremity, 

 where it is flat and is perforated by a transverse foramen. This is possibly 

 a piluitar}' foramen, which thus penetrates the palatal roof as in the Opis- 

 thocojlus Dinosauria as stated by Marsh. 



The rami of the mandible are pressed obliquely against the inferior 

 aspect of the skull, but are separated far enough to permit the palato- 

 pterygoid elements to be seen. These form a rather narrow, flattened rod 

 on each side the middle line, which extend to the robust basipterygoid 

 processes, which look downwards. Each pterygoid then turns abruptly 

 outwards with its edge downwards towards the quadrate, but the speci- 

 men does not permit me to discover whether it reaches that element or 

 not. It sends a robust process to the inner side of the basipterygoid, thus 

 extensively embracing it. The anterior part of the palate is invisible. 



The relations of the dentary and surangular bones are the same as 

 in the specimen No, 1. This specimen shows that the angularand articu- 

 lar are distinct elements. The angular is an elongate element, which is 

 extensively exposed anteriorly on the internal face of the ramus, and then 

 passes to the external face, terminating in an acuminate lamina below the 

 articular cotylus, but not reaching the angle. The articular is only de- 

 veloped anteriorly on the internal border of the ramus, where it extends 

 well forwards, extensively overlapping the angular. The surangular 

 extends posteriorly to the borders of the articular colylus, and spreads 

 out below the articular as though it w^ould enter into the composition of 

 the angle of the jaw, which it does not. It is perforated by a round fora- 

 men near its interior border, and its inferior face is separated from the 

 external face by a prominent longitudinal down-looking angle. The artic- 

 ular cotylus is transverse and is not bifossate. The quadrate contracts 

 immediately above its condyle and is then broken off in the specimen, but 

 it probably has a rather slender shaft. 



There is a large foramen in the internal wall of the ramus which is 

 bounded below by the articular. 



A singular bone occurs in both skulls whose position I cannot deter- 

 mine. It is a slender, strongly curved cylindric cone, which rises from 

 the posterior palatal region and turns upwards, outwards and then back- 

 wards and a little downwards, with a compressed acute apex. It is not 

 articulated with any element at the apex, which lies near the jugal bone, 

 and its basal connections are broken away in both skulls. It is possibly a 

 part of the hyoid apparatus, but if so it is difficult to identify it with any 

 known element. The hypohyal is more appropriate than any other, but 

 I du not make any identification. 



