ME. T. ATXHEY OX AXTHRACOSAUHUS RUSSELLl. 313 



the outer convex side of the maxillary extensions, of which they 

 furnish four inches and a half. The posterior extremities of 

 these bones are peculiar. They are bounded by two lines, meet- 

 ing together at an obtuse angle looking backwards : the outer 

 line begins at a tubercle on the outer border, and runs backwards 

 and inwards; the inner runs from the angle directly inwards, 

 and ends against the quadrate ; it is the margin of a rough space 

 which forms the anterior boundary of a fissure that extends down 

 through the bone, and at the underside of the cranium is seen to 

 divide the condyle into two parts ; one (the larger) on the under 

 surface of the quadrate- jugal, the other (the lesser) on the cor- 

 responding part of the quadrate bone. On the upper surface of 

 the cranium the fissure separates, at that part, the quadrate- jugal 

 from the quadrate. It was, perhaps, filled with cartilage in the 

 living state. 



The quadrate hones are both imperfect, somewhat narrow, being 

 one inch and a half across on their upper surface, but broader 

 below, and elongated, lying along the inner margins of the lateral 

 cranial or maxillary extensions, of which, with the quadrate- 

 jugal, they form the blunt extremity that overhangs the con- 

 dyle for the articulation of the mandible ; of the end of the 

 extensions the quadrate forms two-thirds, and the quadrate-jugal 

 one-third. The inner ends of the quadrate bones articulate with 

 the squamous and the epiotics. The bone of the right was five 

 inches and a quarter in length ; for the space of an inch of the 

 anterior and one of an inch and a quarter of the posterior end 

 have been preserved, and remain in situ, whilst between these 

 pieces the bone is deficient. What remains of the bone of the 

 left side measures three inches in length and one inch and a half 

 in breadth. The posterior margin is thin and free ; and the an- 

 terior articulates with the supratemporal. The upper surfaces 

 of the bones have each a longitudinal ridge, in front of which 

 are the channels leading to the auditory openings. 



The parietals form together an ovoid or subcircular figure, 

 broad behind, flattened and somewhat more pointed in front. 

 They lie immediately behind the frontals, to which they are 

 united by suture; externally they join the postfrontals and the 



