OCR Text |
Show 218 PROF. H. G. SEELEY ON THE [Mar. 21, 5. On the Primitive Reptile Procolophon. By H. G. S e e l e y , F .R .S ., F .Z .S . [Received March 21, 1905.] (Text-figures 30-38.) The Types o f Procolophon.- The two specimens on which Sir R. Owen founded the genus Procolophon in 1876 are in the British Museum of Natural History. The author was uncertain as to the value of the characters in which P. minor differs from P . tri-goniceps, intimating that it may be a young example of that species. The skulls seem to differ in their proportions (text-figs. 30 and 31). P. minor (text-fig. 30) is relatively broader, having the width to length of the skull as 5 to 4. In P. minor the orbits are more distinctly ovate, and placed further forward, being in the middle Type specimen of Procolophon minor, from Donnybrook [the sutures are not so distinct in the specimen as in the figure]. third of the length of the head, in advance of the parietal foramen and scarcely extending behind the lateral borders of the frontal bones; the region in advance of the orbits is relatively short; the quadrate has no expansion backward as in other specimens ; there is no trace of a foramen in the malar arch. Neither fossil gives conclusive evidence of the form of the teeth. Though they are in both types described as conical and pointed, it is not possible to determine the form of the crown when the jaws are closed, as is Text-fig. 30. |