Scientific Investigations Volume 18-19 (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. 1900 Excerpt: ...in spite of the great external differences between them. As mentioned above, Arnoglosxus and Rhomboidickthys have a similar arrangement of the vertebra?. Lepidorhmnbits, on the other hand, is like the Turbot and Topknots in this character, and is therefore widely removed from the two former. In another important character, viz. the ventral fins, Arnoylosstts and Rhombaidichthys are also connected and different from the other genera of the Turbot-group, so that their characters are very clear and definite. The arrangement of the vertebra; which is found exceptionally in the Turbot-group becomes the rule in the Sole-group. Both in the Cynofjlossiii"' and the true Soles, all the species examined showed the htrmapophyses in the abdominal vertebra-. These hn-mapophyses are relatively much shorter than those of the caudal vertebra-, and in Solea (Fig. 9) there is a gradual transition from the one to the other. In addition to the differences in the foimation of the abdominal vertebra-in the various groups, there are also important differences in other characters connected with the alxlominal cavity. The first interha-mal spine which forms its posterior boundary is large and strong in the Plaice-and Halibut-groups, extending in a groove along the first spine almost to the centrum of the first caudal vertebra. The outer end of this spine is very sharp, and may even project through the skin. This character--the presence of an "anal spine"--is employed by Giiuther nd the American writers as a specific character, but the appearance of the spine externally may depend greatly on the condition of the specimen. Thus Giinther declares that there is no anal spine in the Long Rough Dab (D. plutessoidts), whereas the American writers say there is. The latter aga...