lEK. T. ATTHEY OX ASTTHEACOSAUltTJS ETJSSELLI. 31 7 



distance behind the external nasal orifices, internal to and very 

 near the onter margin of the cranium, though internal to the 

 maxillary bone ; whereas in Anthracosaurus the channel from 

 the external nasal orifices leads inwards and backwards towards 

 the middle line, and appears to have been carried further back- 

 wards under the pterygoids to near the posterior end of the 

 presphenoid. 



The large palatine foramen of the above-named Labyrintho- 

 donts does not exist, as already noticed, in Anthracosaurus. 



With respect, however, to the backward position of the nares, 

 it may be as well to leave this for the present an open question, 

 until a specimen is found with the bones of the under surface of 

 the skull better disposed for advantageous observation. "With 

 all the respect due to the opinion of so learned and skilful a 

 palaeontologist as Professor Huxley, my humble opinion is that 

 the posterior nares will be found as far back as the posterior end 

 of the presphenoid. 



Indeed, I may add that I have a very interesting specimen, 

 comprising the whole of the right nasal bone of Anthracosaurus, 

 showing both the upper and under surfaces, and measuring four 

 inches in length. The external angle of its anterior end shows 

 a part of the margin of the external nasal orifice ; and the roof 

 of the channel leading inwards and backwards from it is dis- 

 tinctly visible along the whole length of the bone. Now, as no 

 opening exists on the under surface of the roof of the mouth, 

 the nasal channel must be continued on to the back of the 

 palate. 



The right maxilla is narrow and eleven inches and a half long, 

 and extends from the prgemaxilla to two inches and a half from 

 the posterior angle of the quadrate-jugal. It bears fifteen teeth. 

 For three inches at the anterior end there are no teeth visible, 

 owing to the right ramus of the mandible lying over them. 

 Behind this space the position of six teeth can be made out ; they 

 are two-tenths of an inch apart, and are all broken, but project 

 nearly through the mandible, having been forced into it. The 

 other nine teeth are all about half an inch in length, a little 

 worn at their apices, and placed at irregular distances. 



