Mr. T. Atthey on Anthracosauriis KusseJli. 155 



dible, having been forced into it. The other nine teeth are all 

 about \ inch in length, a little worn at their apices, and placed 

 at irregular distances. 



The left maxilla, — The same force which separated and dis- 

 placed the rami of the mandible has also transferred this 

 maxillary bone to the right margin of the skull, on which it 

 lies imbedded in the matrix, with its anterior end overlying for 

 a short distance the posterior upper border of the right man- 

 dible. Ten and a half inches of its inner surface are exposed ; 

 and about an inch of its anterior end is wanting. It contains 

 28 teeth, nearly all entire, and about \ inch long. They 

 decrease slightly in length backwards, and are irregularly dis- 

 posed in the jaw. 



The palate-hones are about 9 inches long ; a transverse 

 suture divides each into two nearly equal })arts. The anterior 

 borders of the foremost pieces form the posterior margins of 

 the channels leading from the external nasal orifices, and are 

 bounded internally by the vomers and externally by the 

 maxillaries. These anterior pieces have implanted in them 

 the large palatine tusks : that on the right side is covered, as 

 before noticed, by the angular bone of the right mandible ; and 

 that on the left side is broken off at j^o inch above its large 

 expanded base, and is ^ inch thick. Behind this, on each 

 side, is a large depression nearly an inch in diameter, analogous 

 to that existing in the vomerine bones of Loxomma. 



These depressions have been noticed by Prof. Huxley (Quart. 

 Journ. Geol. Soc. vol. xix. p. 58, 1863) as the posterior nares. 

 The posterior pieces or halves of the palate-bone, 4| inches long 

 with an average breadth of 1 inch, are sutured inwardly and 

 backwardly to the pterygoids and outwardly to the maxillaries. 

 At an inch behind the transverse palatine suture is a deep 

 depression, 1 inch long by | inch broad, at a short distance be- 

 hind which the outer margin of the bone is raised up into an 

 alveolus 1^ inch long, containing seven closely set teeth. The 

 first, fifth, sixth, and seventh are all broken off at their apices ; 

 the second, third, and fourth are perfect, and measure | inch 

 in length. The last inch of the bone bears no teeth. The 

 whole surface of the palate-bones is deeply pitted, instead of 

 being tuberculated like the vomers, as has already been said. 



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

 of Anthracosaurus, 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. 



