MR. T. ATTHEY OX ANTHRACOSATJRTTS RUSSELLI. 319 



In another specimen of the anterior portion of the palate-bone 

 of Antliracosaurus, in my cabinet, two large palatal teeth or 

 tusks are developed. One occupies the position of the tusk 

 shown in the figured specimen; the other springs, as it were, 

 from the depression behind it. In the specimen figured, the 

 posterior tooth has been shed; and the depression shows the 

 position it had once occupied. 



Since the paper on Loxomma appeared, I have met with a 

 similar occurrence of two teeth in the right vomer of that Laby- 

 rinthodont. 



The pterygoids are long bones united in front to the vomers ; 

 and if the skull had not been so severely crushed, they would 

 probably have been seen united by suture along nearly the whole 

 of their inner margins. As it is, they have been dislocated ; 

 and their well-preserved margins can be observed pressed up to 

 the level of the upper edge of the presphenoid, which projects 

 between them on the median line. By their outer borders they 

 articulate with the palate and jugal bones ; and their posterior 

 margins form the anterior and inner borders of the supratemporal 

 arches. 



From under the inner margins of the above pieces, which have 

 been widely separated, there curves inwards and backwards, on 

 each side, a short strong piece of bone, which ends in a truncated 

 extremity that is somewhat concave. These bones are very dis- 

 tinct, difficult of determination, and may have been for muscular 

 attachment or osseous articulation. Their ends are parallel with 

 the suture connecting the pre- with the basisphenoid. 



The presphenoid is a long narrow ridge of bone on the median 

 line, extending forwards from the anterior end of the basisphenoid, 

 to which it is united by a transverse suture for seven inches. It 

 is articulated above to the under surfaces of the nasals and 

 frontals; from the posterior end of the upper border, one inch 

 and a half in depth, an ascending process on each side passes up 

 to the under surface of the parietals. Its inferior margin is, for 

 two inches posteriorly, rounded off; it is there nearly half an 

 inch in width ; and the anterior end of the bone is one-tenth of 

 an inch in width. At the distance of half an inch from its 



