Licence: Public Domain Mark
Credit: Further observations on Pareiasaurus / by H.G. Seeley. Source: Wellcome Collection.
Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.
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![be in P. hombidens (‘Phil. Trans.,’ B, 1888, Plate 15). I have no doubt that the anterior pair of bones which lie between the premaxillaries and the pterygoids are the vomera. They contribute, with a narrow horizontal palatal plate of the maxillary bones, to circumscribe^the large anterior comma-shaped (,) palatal vacuities (Plate 20, fig. ]). The sutures cannot be clearly traced, but these bones probably meet in the median line in front of the pterygoids. The palatines are not clearly defined, but must be placed laterally posterior to the palatal vacuities. Behind the palatine, and between the pterygoid and malar regions, there is a postero-lateral expansion of the horizontal plate of the palate, but no proof that it corresponds to the transverse bone. The anterior palatal vacuity is only complete on the right side, where it terminates in a rounded posterior comma-like head, divided from the corresponding vacuity on the opposite side hy a bony interspace 6 centims. wide. The vacuity is 11 centims. long and 4 centims. wide. This structure of palate is best compared to the condition in Mammals, though approximated to in Bhynchocephalia, Teleosauria, &c. There is no trace of a division between the posterior nares, which form a channel between the brain-case above and the palatal plate below. The surface of the palate in the mouth is studded over with small, cylindrical, pointed, enamelled teeth; and there is a large number of recurved teeth, packed more closely, which are arranged in parallel rows upon elevated ridges, and suggest the palate of an osseous Fish rather than the palate of any existing Beptile. The arrangement of these teeth is as follows :—First, there is a median longitudinal channel in the palate, measuring more than 20 centims. to the posterior nares; it is wide in front, constricted in the middle, and widens posteriorly to 2'5 centims. Teeth are arranged parallel to this channel. Two rows of teeth appear to originate upon the inner margin of the vomerine bones. They are at first large, and then small, the small teeth being developed as far back as the vomerine bones, or for about 10 centims. External to these short rows are two other rows, about 2 centims. apart, which extend backward to the outer angles of the posterior nares, from which point two small short rows of six or seven teeth each, converge forward down the median channel. The inner of these rows is 12 centims. long, and the outer 18 centims. long. External to the double or treble parallel ridges is a shallow V-shaped depression on each side of the palate, which is wide anteriorly towards the palatal vacuities, and narrows posteriorly, to a deep groove. The whole of these spaces are covered with scattered teeth. They are bordered externally by two short ridges, about 9 centims. long, carrying close-set teeth; they unite posteriorly, enclosing a narrow space, which is more than a centi- metre wide anteriorly. These double ridges diverge forward and outward to the posterior angle of the maxillary bone, and are regarded as carried upon the palatine bones. External to the outermost ridge there is a very deep channel, with a vertical border, flanked externally by a convex surface, margined on its hinder border by an oblique row of teeth diverging forward and outward. An excavation runs far under this plate, and rises into a channel above, which has the T-shaped form of the audi-](https://iiif.wellcomecollection.org/image/b22417278_0011.jp2/full/800%2C/0/default.jpg)
