| OCR Text |
Show 2 2 6 PROF. H. G. SEELEY ON THE [Mar. 21, palate (text-fig. 34, p. 225), which Dr. Schonland numbered 1, the premaxillary bones extend backward in a wedge between the maxillary bones, so that the vomerine teeth are behind the middle of the maxillary teeth. The vomerine teeth, instead of covering the vomera as in P. laticeps, or forming a close-set group as in R,. 794, P. cuneiceps, diverge backward in two rows from two strong teeth in front separated by a well-marked median groove. There are five or six teeth in each row. Internal to these are parallel shorter rows, which similarly begin with two stronger teeth in front. Further, in the Donnybrook specimen the pterygoid bones separate in an arch (text-fig. 33, p. 224) which is three-fourths of a circle, round which there is a semicircular row of small teeth. But in the Fernrocks palate this median vacuity is bordered by a pair of prominent ridges which diverge backward in a V-shape, each carrying six or seven teeth. These rows are flanked laterally by parallel rows of teeth, which complete the form of a letter M (text-fig. 34). The lateral rows appear to be upon the palatine bones. Text-fig. 35. Outline shojving the truncated snout of Procolophonplatyrhinus, from Fernrocks. The other examples of skulls which have come into my hands from Fernrocks, such as those numbered by Dr. Schonland 2, 12, 13, all differ from the Donnybrook specimens in having the preorbital region of the skull much wider and flatter above, without any indication of the tapering conical snout which is found in all the described species. This character (text-fig. 35) may be conveniently expressed in the name Procolophon platyrhinus for the flat-nosed species, with the region of the nasal bones forming a flattened truncated prolongation of the frontal region, with the postorbital region long and wide. A longer flat preorbital region is seen in another skull (text-fig. 36). If referable to Procolophon, it may be named P. sphevorhinus, terminating in a vertical wedge in front, |
