OCR Text |
Show 1876.] DR. J. V. HAAST ON MESOPLODON FLOWERI. 483 is in the first three vertebrae a rounded apophysis ; in the next vertebrae it gradually enlarges, becoming, as in Epiodon nova-zea-landia, laterally compressed, showing one strongly marked process pointing upwards and forwards, as well as a well indicated and posteriorly situated articulation for the tubercle of the ribs. A separation into two distinct processes takes place in the eighth, the forward or anterior process of the apophysis now appearing as the metapophysis, and its lower or posterior process forming a lower transverse process, starting as a small rounded prominence from the anterior border of the upper portion of the body, and on which the articular surface for the eighth rib is situated, directed obliquely backwards. In the ninth vertebra this separation is still more accomplished, the metapophysis being well developed, and the transverse process, which springs now from near the centre of the body, although thicker and more rounded than those of the succeeding vertebrae, takes already its usual form. It has an articular surface for the ninth rib ou its posterior end, with the same direction as in the preceding one. The tenth vertebra, which is the largest of the series, has a very large transverse process, depressed and broad, on the edge of which the tenth small rib obliquely articulates. This transverse process is the broadest and longest of the whole series of vertebrae-those of the lumbar region, beginning with the first, getting by degrees shorter and narrower. The transverse process of the ninth thoracic vertebra has a horizontal and somewhat backward direction ; that of the tenth stands straight; whilst the same process in the lumbar and in the first series of the caudal vertebrae has, besides a slightly downward, also a forward direction. The bodies of the thoracic vertebrae up to the seventh have a flattened lower surface, after which a keel starts on the eighth, which is well pronounced on the ninth and tenth. Lumbar Vertebrce. The ten lumbar vertebrae resemble each other very much in form. Gradually they become more elongated, the first having an anteroposterior length of 4*55 inches, and the eighth of 6*30 inches, after which they shorten again a little. They possess each a median keel, and are compressed in the centre below the transverse process. The spinous processes are large and high, increasing to the eighth, which is 11*50 inches high, after which they slightly decrease. The arches arise from the centre of the bodies, thus differing from Berardius and Epiodon, where they have a more anterior position. Caudal Vertebra. There are nineteen caudal vertebrae, of which the first ten have a deep channel running along their low?r surface. The spinous processes gradually lose in height, that of the tenth vertebra consisting only of a slight excrescence. The lower transverse processes also shorten by degrees, so that in the sixth they are represented by a small horizontal ridge, which is only faintly indicated in the seventh. In the eighth, ninth, and tenth vertebrae all signs of such processes |