346 Messrs. Hancock & Atthey on Reptile-and Fish-Bemains XLV. — Notes on the Remains of some Reptiles and Fishes from the Shales of the NortJiumherland Coal-field. By Albany Hancock, F.L.S., and Thomas Atthey. [Continued from p. 278.] [Plates XIV., XV., XVI.] Rhizodus Hihherti^ sp., Agassiz. The teetli of tliis species have not yet been found in the shales of our neighbourhood ; but large scales Avhich appear to belong to it are not by any means uncommon at Newsham and Cramlington. They are rarely found perfect ; sufficient examples have, however, been obtained to enable us to identify them with the scales of i?A^^06?(<si7^iier<^ described by Dr. Young in vol. xxii. p. 599 of the ' Journal of the Geological Society.' The largest we have seen measures three inches in diameter ; they usually appear quite thin, and are of an irregularly rounded form with the front margin a little flattened, the pos-terior a little produced, and the sides only slightly arched. The surface is marked with numerous sharp concentric lines of growth and minute, close, radiating stria3, requiring a good lens to show them. There are also a few distant delicate ridges, extending from the centre to the anterior border. Such scales are undoubtedly in an imperfect condition. When complete, they are considerably thicker, and the under surface has a smooth bony appearance, exhibiting nevertheless decided concentric lines of growth, a subcentral elongated boss, and numerous small pits, particularly on the posterior portion, which, however, we have never seen in a good con-dition. On the posterior or exposed area there are a few ob-scure, irregular, radiating ridges, which are rendered still more indistinct by the granular tubercles that are scattered over the surface. The smaller scales, which are usually about one inch and three-quarters long and scarcely one and a half inch wide, have all the characters of the large scales ; but they are ge-nerally more elongated in form, and the minute radiating strise are coarser. Besides these scales, several bones have occurred at News-ham, which, from the peculiar surface-sculpture, most probably also belong to this poAverful fish. We were anxious to prove this by comparing them with some authenticated fragment of the bone of Rhizodus showing the surface-ornament, but have failed in our endeavour. Tliey agree, hoAvever, in this respect so well with the descriptions, that we cannot hesitate to assign them provisionally to this species. Of the two most remarkable bones of this collection, one
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