Dental Record (Volume 11); A Monthly Journal of Dental Science Art and Literature (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1891 Excerpt: ... HISTOLOGY OF THE TEETH OP MESOPLODON LAYARDI. By G. W. Watson, L.D.S. Professor Sir William Turner asked me to try my hand at taking some micro-photographs of sections of the teeth of this rare whale, which I very willingly did, and it enables me to bring before your notice the structure of the teeth of this interesting and unique animal. Three specimens of Mesoplodon Layardi were brought home by the "Challenger" expedition, and were handed over to Sir William Turner for description. In June, 1870, he read a paper before the Royal Society descriptive of the structure and arrangement of the teeth of this cetacean. Layard's whale, though very rare now, seems to have been pretty common at one time, numerous fossilised fragments of its beaked jaws having been obtained from the Red Cray, Norfolk. Their common characters are long narrow beak-like jaws, and prominent elevated heads (hence the name bottle-headed whale), and they range from fifteen to thirty feet in length. In the upper jaw there are no teeth present. Quoting from Professor Sir William Turner's description: --In the lower jaw, at the junction of the symphysis with the body, two teeth protrude from their sockets (as will be seen on diagram). Each tooth consists of a triangular denticle proper, and a strap-shaped shaft: the shaft. laterally compressed as it emerges from the socket. curves obliquely backwards, upwards and inwards, so that its inner concave surface is in relation to the side and dorsum of the beak. As the summit of each tooth reaches the opposite side of middle line, the two teeth cross each other on the dorsum of the beak, and from the polished appearance of the anterior and inner surface of each shaft, it is evident that they must have rubbed against each other, or against the beak in...