Report of the Meeting Volume 9 (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. 1840 Excerpt: ...of the lower jaw I find that the angular bone is continued further forwards before it is covered by the overlapping dental piece than in the Ich. intermedius or Ich. communis, a structure which contributes to the strength of the lower jaw in this gigantic species. The teeth I have not found to exceed 45-45 in the upper and 40-40 in the lower jaw. Their crowns are more frequently found to be snapped off than in the smaller species, a circumstance which is indicative of the greater violence with which they had been used. In the collection of Mr. Johnson of Bristol there is a tooth of the Ich. platyodon which measures two inches and a half in length: its crown, which, as usual, is pretty smooth and compressed, measures one inch. 1839. I The vertebrae have their bodies more compressed in the antero-posterior direction than in most other Ichthyosauri. From the occiput to the iliac bones I count 45 vertebras, and thence to the end of the tail 75 vertebras, making in all 120. From the dentata to the 25th vertebra inclusive, the centrum is characterized by two well-marked tubercles on each side for the articulation of the ribs. It is one of these vertebras which is figured (in the inverted position with the spinal canal downwards) in PI. XIV. of the Philosophical Transactions (1816), illustrative of Sir E. Home's second memoir on the Ichthyosaurus. The remaining vertebral centres present only a single surface for the articulation of the rib: the spinous processes are thicker, shorter, and more rounded superiorly, than in the Ich. intermedius or Ich. communis: their articular processes for mutual interlocking are well developed, especially at the anterior part of the spine. The ribs commence, as usual, at the second cervical vertebra; they increase in length to the ...