1862.] OAVEN REniLIAN REMAINS. 241 



iS^ear the specimen, and near the jaw of Hylonomus (fig. 7a), are 

 specimens of the dermal scutes. They are oval, flattened, smooth 

 and slightly concave on the inner side, with parallel curved stria- 

 tions on the outer surface. 



PL IX. fig. 14 is the dentary bone, with very small, equal, close- 

 set teeth, eleven being in the extent of 2 millimeters ; they best 

 accord in character with those of the upper jaw of Hylo7iomus Lyelli 

 (fig. 5), to which species I believe this lower jaw to belong. 



PL IX. fig. 15 is part of an upper jaw, with teeth less closely 

 arranged, and very small in proportion, to the breadth of the bone. 

 It is of a Hylonomus, and exhibits on the outer surface of part of 

 the bone the pits and radiating furrows which characterize the outer 

 sculpturing of the skull-bones of Archegosaurus. 



" Parcel Xo. 4. — Jaw of a Reptile, supposed to be new." 

 Hylerpeton Dawsoni, Ow. (PL IX. fig. 16). 



This specimen consists of the left ramus of a lower jaw, which 

 has been dislocated from the crushed head, of which the fore end 

 of the left premaxillary (p) is preserved, terminating near the 

 middle of the series of the teeth of the more advanced mandible. 

 A fragment of the left maxillary (m), which has been separated from 

 the premaxillary, overlaps the hinder mandibular teeth. The fore 

 part of the mandible is wanting. The teeth in the remaining part 

 are larger and fewer, in proportion to the jaw-bone, than in Hylo- 

 nomus or Denclrerpeton. They have thicker and more obtusely ter- 

 minated crowns ; they are close-set where the series is complete at 

 the fore part of the jaw, and their base appears to have been an- 

 chylosed 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 side ; 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 

 Hylerpeton, 



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

 longitudinally wrinkled and striate or fibrous character. The outer 

 bonj' wall, broken away from the hinder half of the dentary, shows 

 a large cavity, now occupied by a fine greyish matrix {x), 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 exemplifies 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 

 10 millimeters, or nearly 5 lines. The portion of jaw, figured of 

 twice the natural size, in fig. 17, shows the anchylosis of the base of 

 the teeth in a shallow groove or alveolus : the base of the teeth is 



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