Mr. T. Atthey on Anthracosaurus Russelli. 151 



away from both the upper and under surfaces of these bones, 

 there is no indication of a supratemporal foramen, which is 

 said by Professor Huxley to exist. 



The quadrate-jitgals^ of somewhat rhomboidal outline, lie on 

 the outer convex side of the maxillary extensions, of which 

 they furnish 4| inches. The posterior extremities of these 

 bones are peculiar. They are bounded by two lines, meeting 

 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 ex- 

 tends down thi'ough 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 tlie quadrate-jugal, the other 

 (the lesser) on the corresponding 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 1^ inch 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 b\ inches in length ; for the space of an incli 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 3 inches in length and 1| inch in breadth. The 

 posterior margin is thin and free ; and the anterior 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 pan'etals 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 squamous, and behind the so-called supraoccipitals. The 

 parietal foramen, ^ inch in diameter, lies at about an equal 

 distance from the anterior and posterior borders of the bones. 



The so-called supraoccijyitals are about twice as broad as they 

 are lono- united on the median line, bounded by the parietals 



11* 



