The premaxillaries, which show some obscure traces of a symphysial suture at the median line, anterior to the nasal or naso-palatine vacuities, extend outwards, on each side, for an extent of 2.5 lines and there join the maxillaries. Traces of round alveoli for teeth, some of which are 2 lines in diameter, are visible on the alveolar border of the premaxillaries. The alveolar border is continued by the maxillary bone for an extent of 4.5 inches beyond the premaxillary border, and this border shows still more distinct traces of alveoli, of a circular form, about a line in diameter and rather close set in a single series. The fore part of the orbit is very unequivocally displayed, the smooth inner or under surface of the bone forming that part being entire; and this shows the fore part of the orbit to be formed, partly by the maxillary, partly by the lacrimal or prefrontal bone in close sutural union therewith, a structure which does not exist in any recent or fossil fish with a dentigerous superior maxillary bone. Where the substance of the bone has been detached so far as to expose the external layer in contact with the coal, as, e.g., on the frontal and part of the prefrontal bones, the external surface of those bones is shown to have been impressed by subhemispherical or elliptical pits, from 1 line to 1.5 lines in diameter, and with intervals of half of that extent. This coarsely pitted character agrees with that presented by the other surface of the similarly broad and flat cranium of the labyrinthodonts.
From the characters above specified, therefore, I conclude that this fossil is the fore part of the skull of an extinct family of the labyrinthodonts. It agrees with them in the number, size, and disposition of teeth; in the proportions and mode of connection of the premaxillaries, maxillaries, nasals, prefrontals, and frontals, and in the resultant peculiarly broad and depressed character of the skull. The traces of the nostrils are less definite and satisfactory than the remains of the orbits, bu t the latter appear to be decisive against the piscine nature of the fossil. The fossil also presents the same well-marked external sculpturing as in the labyrinthodonts; and among the genera that have been established in that family, the form of the end of the muzzle, or upper jaw, in the Pictou coal specimen best accords with that in the Capitosaurus and Metopias of von Meyer and Burmeister ([80]).
| Measurements of the Skull of Baphetes planiceps Owen. (Type in the British Museum of Natural History, London.) | |
| mm. | |
| Approximate median length of skull | 136 |
| Width of skull across base of horns | 150 |
| Estimated width across tips of horns | 186 |
| Width of horn at base | 31 |
| Estimated length of horn from base | 80 |
| Width of skull across orbits | 97 |
| Diameter of orbit | 21 |
| Diameter of large tooth alveolus | 7 |
| Diameter of small tooth alveolus | 2 |
Pictou Coal, near Pictou, Nova Scotia, Canada, collected by Dr. J. William Dawson, 1850, and presented by him to the Geological Society of London.
Baphetes minor Dawson.
Dawson, Canadian Nat. and Jour. Sci., n. s., 1870, V, pp. 98, 99.
Type: Specimen in the Peter Redpath Museum, McGill University.
Horizon and locality: Coal formation of Nova Scotia.
The species was based on a lower jaw of an amphibian, of which a cast had occurred in the coarse sandstone of the coal formation between Ragged Reef and the Joggins Coal Mine. It measured 6 inches in length; its surface was marked on the lower and posterior part with a network of ridges inclosing rounded depressions. The anterior part of the jaw contained about 16 teeth, some of which remained in the matrix. These were stout, conical and blunt, with large pulp cavities, and about 32 longitudinal striæ, corresponding to the folds of the dentine. Dawson states that this jaw resembles most closely those of Baphetes and Dendrerpeton, but more especially the former. He regarded it as distinct from Baphetes planiceps, and proposed for it the name Baphetes minor.
Eosaurus acadianus Marsh.