148 Mr. T. Attliey on Anthracosaurus Russelli. 



of the pits or hollows, such as are found in the corresponding 

 parts of Loxomvia, this discrepancy pointing very probably to 

 some as yet unrecognized difterence in the state of tlie integu- 

 ment in these animals. 



The nostrils are openings of about half an inch diameter, 

 and slightly oval in outline. They are bounded in front by 

 the premaxillaries, internally by the nasals, externally and 

 posteriorlv by the inaxillarics. They are 2^^ inches apart ; 

 and a line drawn across the nasal region between the middles 

 of their internal margins is one inch behind the mid point of 

 the snout. They are only half an inch distant from the margin 

 of the jaw, and are placed much further forward than the 

 nostrils of Loxomma. 



The mucus-grooves are two pairs. The anterior pair run 

 backwards and inwards along the inner side of the naso- 

 1 acrymal suture as far as the posterior margias of the nasals ; 

 the posterior are deeper, and appear in two disconnected por- 

 tions along the outer margins of the jugal and quadrate-jugal 

 bones. The anterior pair of grooves are less deep and less 

 distinct than those of Loxomma ; the posterior are deeper, 

 wider, and rougher than those of that Labyrinth odont. 



In Anthracosaurus there is only one pair of mucus-grooves 

 in front, instead of two pairs as in Loxomma ; whilst in the 

 former only these posterior grooves exist. 



In Anthracosaurus the anterior grooves lie, as far as can be 

 seen, entirely on the nasals ; in Loxomma the anterior grooves 

 lie nearly altogether on the premaxillaries, and the posterior 

 on the maxillary and lacrymai bones. 



The orbital vacuities, broader in front than behind (in fact, 

 somewhat heart-shaped), are placed 8| inches behind the snout, 

 are 2 inches long and 1| inch broad ; at their anterior margins 

 are two concaWties (the inner rather smaller than the outer), 

 having a sharp prominence between them ; this, with a similar 

 but smaller projection at the posterior margin of the vacuity, 

 seen best on the right side, shows where the ligament bounding 

 the true orbit on the outer side had been attached. 



The inner margin of each orbital vacuity is slightly arched, 

 the concavity looking outwards ; the outer margin is also 

 arched, and looks inwards and slightly forwards. These end 

 posteriorly in a small concavity, the inner extremity of which, 

 coming forwards, joins the inner margin of the vacuity, forming 

 with it the posterior projection above mentioned. 



The true orbit and the rest of the vacuity are very much 

 smaller, and placed further back than in Loxomma. The eye, 

 therefore, of Anthracosaurus must have been very much less 

 than that of Loxomma ; the part of the vacuity not occupied 

 by the eye points outwards instead of forwards. 



