OCR Text |
Show 1885.] MR. J. B. SUTTON ON HYPERTROPHY. 441 the dorsum of the beak ; and from the smooth appearance of the anterior border and inner surface of each shaft, it is evident that they must have rubbed against each other, or against the beak during the movements of the lower jaw in the act of opening the mouth." ° Besides this specimen, Prof. Turner also received the skull and Fig. 8. A magnified vertical transverse section through the summit, of the shaft of the tooth of the adult Mesoplodon layardi. The tooth is made up of the following tissues, from above downwards: a. cement; b, vaso-dentine ; c, a layer of more opaque modified vaso-dentine ; d, dentine ; e, modified vaso-dentine of the centre of shaft. (After Turner.) parts of the skeleton of an immature Mesoplodon layardi, which enabled him to determine the nature of the various parts of this strange tooth. Each tooth in this immature specimen was two inches from |