152 Mr. T. Atthey 07i Anthracosaurus Russelli. 



in front, by the squamous and then the epiotics externally, by 

 the true occipitals beneath the posterior border of the eranium ; 

 and they form, Avith the epiotics, the posterior concave border 

 of the occiput. 



T/ie epiotics, somewhat rhomboidal, with the posterior ex- 

 ternal angles produced backwards and outwards, forming the 

 external angles of the true cranium, and broader than long, are 

 sutured in front to the squamous, internally to the so-called 

 supraoccipitals, and externally for a third of their length to the 

 quadrates, the outer two thirds being free. Behind and 

 beneath they are united by suture to the upper surface of the 

 occipitals. A small portion of the outer and posterior margins 

 of each of these bones is wanting, having been broken off. 



I have not ventiu'ed to mark out, even by dotted lines, what 

 I consider to have been the original outline of these parts. 



Under surface of the skull (Plate IX.). — This entire sur- 

 face, excepting the premaxillary part, has suffered great vertical 

 depression. The median suture, uniting the premaxillaries, is 

 distinct, and is seen to be continued fm-ther back between, first, 

 the vomers and then the pterygoids. On the right side of the 

 median line the palate is nearly perfect ; on the left, the maxil- 

 lary bone is wanting. Nearly the whole of the praemaxilla, the 

 nasal channel, the entire palatal tooth, a portion of the palate- 

 bone, and the corresponding part of the maxilla of the right 

 side are unfortunately covered by the angular bone of the right 

 mandible, which has been thrown obliquely along that part of 

 the inferior surface of the cranium. 



The above parts are all exposed and well seen on the left 

 side. Besides this, the posterior piece of the left palate-bone, 

 which bears a series of small teeth, has been shifted from its 

 natural position, and lies on the posterior part of the upper 

 surface of the same side of the cranium, as was noticed in the 

 description of the upper cranial surface. 



Owing to the absence of this portion of the palate-bone, with 

 a portion of the corresponding pterygoid, from its natural site, 

 a portion of the left orbital vacuity can be seen through from 

 below ; also the imder surfaces of the lacrymal, prefrontal, and 

 jugal bones can be seen united by their sutures. On the right 

 side a good many of the posterior teeth of the maxilla are in 

 situ, and parallel to them are seen the teeth of the posteiior 

 division of the palate-bone. On this side, also, a small portion 

 of the orbital vacuity is seen through from below, and the under 

 surface of its inner margin is well defined. 



The supratemporal arch of the right side shows part of the 

 under surface of the supratemporal and the whole of that of the 

 quadrate-jugal bone, the sutures of which are nearly all, on 



