BAPHETES Ow.
Sp. Baphetes planiceps.—In January 1854 the writer com municated to the Geological Society of London a description of part of a fossil cranium of an animal, from the Pictou coal, Nova Scotia, measuring 7 inches across the orbit. From the characters then specified, the fossil was determined to be the fore part of a skull of a sauroid Batrachian of the extinct family of the Labyrinthodonts. It agreed with them in the number, size, and disposition of the teeth ; in the proportions and mode of connection of the premaxillaries, maxillaries, nasals, pre frontals and frontals ; and in the resultant peculiarly broad and depressed character of the skull, the bones of which also present the same well-marked external sculpturing as in the Labyrinthodonts : and amongst 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 accorded with that in the Capitosaurus and Metopias of Von Meyer and Burmeister. But the orbits had been evidently larger and of a different form than in the reptiles so called ; and, for the convenience of distinction and reference, it was proposed to name the fossil Baphetes planiceps (36Arree, I dip or dive), in reference to the depth of its position and the shape of its head.
Being thus introduced at the carboniferous period to the labyrinthodont order, which attained its full development in the triassic period, the more decisive evidences and typical illustrations of that extinct group of reptiles will next be described.
Genus LABYRLNTHODON, Ow.
At the period of the deposition of the new red sandstone, in the present counties of Warwick and Cheshire, the shores of the ancient sea, which were then formed by that sandy deposit, were trodden by reptiles having the essential bony characters of the modern Batraellia, but combining these with other bony characters of crocodiles, lizards, and ganoid fishes ; and exhibiting all under a bulk which, as made manifest by the fossils and footprints, rivalled that of the largest crocodiles of the present day. The form of the largest Labyrinthodonts, if we may judge by the great breadth and flatness of the skull, and the proportions of certain bones, seems to have been something between that of the toad or land-salamander.
The smooth-skinned Batrachians have no fixed type of exter nal form like the existing higher orders of reptiles, but some, as the broad and flat-bodied toads and frogs, most resemble the Chelonians,especially the soft-skinned mud-tortoises (Trionyx); other Batrachians, as the Cceeilice, resemble Ophidians ; a third group, as the newts and salamanders, represent the Lacertians ; and among the perennibranchiate reptiles there are species (Siren) which combine with external gills the mutilated con dition of the apodal fishes.
Thus it will be perceived that, even if the entire skeleton of a Labyrinthodont had been obtained, there is no fixed or characteristic general outward form in the Batrachian order whereby its affinity to that group could have been determined.
The common characters by which the Batrachians, so di versified in other respects, are naturally associated into one group or sub-class of reptiles, besides being taken from the condition of the circulating and generative systems, and other perishable parts, are manifested in modifications of the skeleton, and principally in the skull. This is joined to the atlas by the medium of two tubercles, developed exclusively from the ex-occipitals ; the bony palate is formed chiefly by two broad and flat bones (fig. 65 a, c), called " vomerine," and generally supporting teeth. It is only in the Batrachians among existing reptiles that examples are found of two or more rows of teeth on the same bone, especially on the lower jaw (Ccecilia, Siren). With gard to vertebral characters, no such absolute batrachian modifications can be duced as those above cited from the anatomy of the cranium. Some Batrachians have the vertebrae united by ball-and-socket joints, as in most recent reptiles ; others by biconcave joints, as in a few recent and most extinct Saurian. Some species have ribs, others want those appendages ; the possession of ribs, fore, even if longer than those of the Coecilia, by a fossil reptile combining all the essential batrachian characters of the skull, would not be sufficient ground for pronouncing such reptile to be a Saurian. Much less could its saurian nature be pronounced from the stance of its possessing large conical striated teeth : the ordi nary characters of size, form, number, and even of presence or absence of teeth, vary much in existing Batrachians ; and the location of teeth on the vomerine bones is the only dental character in which they differ from all other orders of reptiles.