I, AND ANIMALS OF THE COAL 1T.IU0D. 381 



They have thicker and more obtusely terminated crowns; they an 

 close-set where the series is complete at the fore part of the jaw, and 

 their base appears to have been anchylosed to shallow depressions on 

 the alveolar surface. The shape of what is preserved of the upper 

 jaw affords the only evidence, and not very decisively, that the present 

 fossil is not part of a fish. It inclines the balance, however, to the 

 reptilian sale; and, accepting such indication of the class-relations of 

 the fossil, it must be referred to a genus of Reptilia distinct from those 

 it is associated with in the Nova Scotian coal, and for which genus I 

 would suggest the term Ilylerpeton. 



" A small part of the external surface of the dentary bone shows a 

 longitudinally wrinkled and striate or fibrous character. The outer 

 bony wall, broken away from the hinder half of the dentary, shows a 

 large cavity, now occupied by a fine greyish matrix, with a smooth 

 surface, the bony wall of which cavity has been thin and compact. 

 We have here the mark of incomplete ossification, like that in the 

 skeleton of Archegosaurus. The crushed fore part of the right dentary 

 bone, with remains of a few teeth, is below the left dentary, and ex- 

 emplifies a similar structure. The teeth slightly diminish, though 

 more in breadth than length, towards the fore part of the series : here 

 there are nine teeth in an alveolar extent of ten millimetres, or nearly 

 five lines. The base of the teeth is longitudinally fissured, but the 

 fissures do not extend upon the exserted crown. In their general 

 characters, the teeth manifest at least as close a resemblance to those 

 of Ganocephala as of Lacertia or any higher group of Reptilia ; whilst 

 their mode of implantation, with the structure and sculpturing of the 

 bone, weigh in favour of its relations to the lower aud earlier order 

 of the cold-blooded Vertebrates." 



I can add to the above description only a few facts obtained from 

 careful examination of other fragments imbedded in the matrix. One 

 of these is a portion of a maxillary bone. It has teeth similar to those 

 of the lower jaw in form, but the last but one is twice the size of the 

 others, and seems to have been implanted in a deep socket. All of 

 the teeth have large pulp cavities, and the inner surface of the ivory 

 is marked with slight furrows which are represented by ridges on the 

 outer surface of the stony matter filling the pulp cavities. The ivory 

 of the teeth, however, which is very much coarser than that of the 

 species of Hylonomus, presents in the cross section a simple structure 

 of radiating tubes. The surface of the cranial bones, of which some 

 fragments remain, is marked in the same striate manner alluded to 

 above by Professor Owen. The microscopic structure of the bone is 

 much coarser than that of Hylonomus or Dendrerpeton, the cells being 



