The Natural History of Animals The Animal Life of the World in its various BY J. R. AINSWORTH DAVIS, M.a. TRINITY COLLEGE, CAMBRIDGE PROFESSOR IN THE UNIVERSITY OF WALES, AND PROFEssor of zoOLOGY AND HALF-VOL. V UNIV. OF LONDON THE GRESHAM PUBLISHING COMPANY 34 SOUTHAMPTON STREET, STRAND 1903 CILIARY MOVEMENT-Cilia and Flagella. Cilia of Protozoa. Cilia of Comb-Jellies (Ctenophora) and Planarian Worms (Turbellaria). Ciliated Larvæ. Distri- bution and Use of Cilia among Higher Animals. Flagella of Protozoa and MUSCULAR MOVEMENT-Nature and Mode of Action of Muscle-Fibres. Muscular Tissue. Unspecialized Muscle of Freshwater Polype (Hydra). Unstriated Muscle, its Distribution and Uses. Heart Muscle. Striated Muscle, its Dis- SWIMMING OF JELLY-FISH (Hydrozoa)-Structure of a Simple Jelly-Fish or Medusa. Compound Jelly-Fish (Siphonophora). Comb-Jellies (Ctenophora)—Beroë, Cy- SWIMMING ANNELIDS (Annelida): Leeches (Discophora)- Medicinal Leech (Hirudo). Bristle-Worms (Chatopoda)-free-living forms: Tomopteris SWIMMING ECHINODERMS (Echinodermata)-Larval forms. Feather-Stars. Free- 301522 SWIMMERS AMONG LOWER CRUSTACEANS (Crustacea)-Nauplius Larva. Mussel- - HEAD-FOOTED MOLLUSCS (Cephalopoda)-Cuttle-Fishes and Squids. Argonaut PRIMITIVE VERTEBRATES (PROTOCHORDATA) AS SWIMMERS: Ascidians (Uro- FISHES (PISCES) AS SWIMMERS: Primitive Swimming of Lampreys and Eels. Sharks and Dogfishes (Elasmobranchii)-Action of Unsymmetrical Tail-fin. Ordinary Bony Fishes (Teleostei)-Adaptations to Swift Progression, Action of Symmetrical Tail-fin, Mackerel (Scomber). Flat-Fishes and Eels. Sea-Horse (Hippocampus). Pectoral Fins of Skates and Rays (Elasmobranchii) AMPHIBIANS (AMPHIBIA) AS SWIMMERS-Tail-swimming in Tadpoles, Newts, and Salamanders. Eel-like Amphibians-Three-toed Salamander (Amphiuma), Olm (Proteus), Mud-Eels (Siren and Pseudobranchus). Leg-Swimming in REPTILES (REPTILIA) AS SWIMMERS: Crocodiles and Alligators (Crocodilia)-Nile BIRDS (AVES) AS SWIMMERS-Structural Adaptations to Swimming |