150 Sir J. W. Daivson — On Bendrerpeton Acadianum, etc. 



than in most other amphibians. The bone which I suppose to be 

 the parasphenoid has a long axial process, and the posterior end 

 moderately broad. On the other hand, it is certain that the skull 

 has an open parietal foramen, has a group of small palatal teeth, and 

 has two occipital condyles. 



2. As to the trunk. The vertebrae are long, hour-glass-shaped, 

 biconcave, and ossified exteriorly, with large and broad neural 

 and lateral processes. The ribs are well developed, curved, and 

 with a double head. The scapular and pelvic bones are large, 

 especially the latter, which has a very broad well-ossified principal 

 bone, perhaps the ilium. The pelvic bones thus resemble those 

 of Diplovertehron ^ of Fritsch, which is, however, an animal very 

 different in other respects. I regret that I have had no means of 

 ascertaining whether the pelvis of 11. Lyelli was attached to one 

 sacral vertebra or more. The large size of the pelvis would, how- 

 ever, render its attachment to a single vertebra improbable, and in 

 the skeletons on the slabs (a) and (h), Fig. 4, there are in the 

 vicinity of the pelvis pairs of vertebrae attached to each other in 

 such a manner as to suggest that they were permanently united. 



3. The limb-bones and ribs have a thin and hard outer bony coat, 

 the interior being usually filled with calcite darkened by oiganic 

 matter, probably remains of cartilage. The bones of the limbs and 

 feet are long and slender, with well-ossified extremities, and .their 

 forms indicate slender limbs and active habits. The hind-limb in 

 particular is somewhat larger than the anterior ; and this with the 

 size of the pelvis indicates a form of body broader behind, narrower 

 in front. In farther connexion with this I have remarked in former 

 papers that the skeletons of this animal always lie on the side, 

 indicating that the body was flattened, not vertically, but laterally, 

 as in some Lizards. This I regard as an important diagnostic 

 character for SyJonomus, and it does not seem to apply to the genus 

 HyJopIesion of Fritsch, which is flattened vertically, as well as much 

 inferior in development of pelvis and limbs. 



4. As to dermal covering, Eylonomus has the abdomen protected 

 by bony scales, but differing in form and probably in arrangement 

 from those of Dendrerpeton. The covering of its upper part was 

 however peculiar to itself, presenting a perfectly scaly surface of 

 true corneous scales and with ornamental tubercles and spiny 

 epaulettes on the shoulders, of which there is no trace in any other 

 known amphibian, recent or fossil. It also possessed pendant fringes 

 of. cuticle like those of Dendrerpeton. 



In connexion with this statement, I copy here (Fig. 4) from my 

 " Airbreathers of the Coal Period " an illustration of the scattered 

 bones of a skeleton of Hylonomus Lyelli, and some of the parts 

 enlarged, which will serve with the accompanying description to 

 illustrate some of the structures. I have given in the paper above 

 referred to, in the "Transactions of the Eoyal Society," a copy of a 

 portion of the scaly armour from a micro-photograph. 



^ Plate 52, Fauna der Gaskohle. As interpreted by Fritsch, the ilat bone is called 

 the pubis. 



