894 MESSRS. HANCOCK AND ATTHEY 



have been pretty regular in size, and are placed a little apart 

 from each other. These two mandibular fragments are each 

 upwards of two inches long ; so that if one of them be joined to 

 the large portion of the mandible already described, we have 

 the dimensions raised to twelve inches ; but as we have no 

 means of determining how much of the proximal extremity is 

 wanting, it is difficult to say what was the real length of this 

 formidable jaw when perfect. Its massiveness, however, is suf- 

 ficiently evident, as the bone of the anterior fragment is nearly 

 an inch thick. 



The left praemaxilla is also very well displayed, lying across 

 the large mandibular fragment. It is three inches and a half 

 long and one inch and three-quarters wide. The anterior ex- 

 tremity is rounded ; and close to the front margin there is, as 

 in the mandible, a laniary tooth, which is small, however, in 

 comparison with that of the latter ; it is seven-eighths of an inch 

 in length, and is proportionately narrow. This tooth is suc- 

 ceeded by about twenty minute teeth, one eighth of an inch long, 

 or thereabouts, which are very regularly arranged at a little dis- 

 tance from each other. 



Mixed up with the above are many other bones, belonging 

 apparently to the skull ; but they are too much broken up to 

 admit of exact determination ; the right prremaxilla, however, 

 with its anterior laniary tooth, can be discovered amidst the 

 commingled mass. 



The surface of the more perfect bones exhibits the peculiar 

 tubercular sculpture originally described ; and the characters of 

 the teeth show no variation from (indeed they are precisely si- 

 milar to) those at first pointed out as distinguishing the species. 



Two gigantic jugular plates were obtained at the same time, 

 associated with the above remains, though not on the identical 

 slab. We do not hesitate to assign them to Archichthys, not 

 more on account of their association than from the character 

 of the surface -structure, which agrees with that of the other 

 bones of this fish, and that we know of no other species found 

 in our coal-shales to which they can belong. The size alone 

 would seem sufficient to determine the question. Megalichthys 



