Manual of Geology

Manual of Geology

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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. 1866 edition. Excerpt: ...of Fishes in the Ichthyozoic erio. P The Holo tychius is a Ganoid, and the type of the family I-Ioloptychidae, which possessed the folQ lowing characters: --The rays of the fins hollow; skeleton cartilaginous; completely covered from the occiput to the tail with sculptured enamelled scales; large curved teeth, mixed with smaller ones; all the fins Well developed, indicating active and voracious habits; eye placed over the mouth, giving a snake-like, reptilian character to the countenance. There can-be no better type of the four footed Fish than the Holoptychius, whose pectoral and ventral fins were real arms and legs, capable of important uses; while the dorsal, anal, and caudal fins, on which the balancing and steerin of the animal depend, are so develo ed as to lead to the conclusion that this mail-clad) fish possessed swiftness and dexterity quite in keeping with the carnivorous tastes indicated by his teeth. As a type of the Neozoic Fishes, I have chosen the Semiophorus velicans, Fig. 23, of the Tertiary Limestone of Monte Bolca. This Fish is a Ctenoid Teleostean, of the family Chaatodontidae, and is characterized by the enormous length of its dorsal and ventral fins, the rays of which are soft, with the exception of the anterior ones; the anal fin is small, and the pectorals seem to be altogether absent. Vith respect to the Palaeontological laws with which we concluded the preceding ecture, it will be observed that the fossil Fishes establish the first law in as complete and satisfactory a manner as can be desired; but that they form a remarkable exception to the second law, as there can be little doubt that the Palaaozoic Fishes a roach the reptilian type more closely than the Flleozoic Fishes; and that the are entitled, if on this account..show more

Product details

  • Paperback | 118 pages
  • 189 x 246 x 6mm | 227g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236505115
  • 9781236505118