. Activités des animaux ; un premier livre au zoo ?logie. Zoologie ; le comportement animal. ANIM UNICELLULAIRES/suspension et d'éponges. 125. Fig. 109.-Spicules éponge. Ces cavités sont fournis avec des flagelles qui par leur mouvement constant que l'eau se déplaçant le long de l'inhalent de l'exhalent les ouvertures. Comme l'eau passe le long de celui-ci apporte à la portée de t h e minute flagelles les animaux et les plantes qui sont saisis et repoussé dans les cellules où ils sont dissous et assimilé de la même manière que la nourriture de l'Amibe est assimilé dans sa cellule. La respiration, aussi, est exploitée par l'individu cell

• Contributeur: Central Historic Books / Alamy Banque D'Images
• ID de l’image: PG0A59
• Taille du fichier: 7,1 MB (157,5 KB Téléchargement compressé)
• Autorisations: Modèle - non | Propriété - non
• Dimensions: 1741 x 1435 px | 29,5 x 24,3 cm | 11,6 x 9,6 inches | 150dpi

Informations supplémentaires

Cette image appartient au domaine public, ce qui signifie que le droit d’auteur a expiré ou que le titulaire du droit d’auteur a renoncé à ses droits. Les frais facturés par Alamy couvrent l’accès à la copie haute résolution de l’image.

Cette image peut avoir des imperfections car il s’agit d’une image historique ou de reportage.

. Animal activities; a first book in zoo?logy. Zoology; Animal behavior. ONE-CELLED ANIM/ILS AND SPONGES. 125. Fig. 109.—Sponge Spicules. these cavities are provided with flagella which by their constant movement keep the water moving along from the inhalent to the exhalent openings. As the water passes along it brings within reach of t h e flagella minute animals and plants which are seized and pushed back into the cells where they are dissolved and assimilated in much the same way as the food of the Amoeba is assimilated in its cell. The breathing, too, is carried on by the indi- vidual cells as in the Amoeba. Nutriment from the endoderm cells is passed along from cell to cell to nourish the rest of the body. From this nutriment the material for building the skeleton is secreted. This skeleton is often in the shape of spicules of hard material. Spicules may be calcareous, silicious, or horny, producing these three kinds of sponges. Only the horny or keratose sponges are of any commerical use. So nearly independent are the individual cells com- posing the sponge-structure that if a few of them be separated from the original body, they go on living and divide and subdivide, making new cells and build- ing the structure of a new sponge. If a living sponge be cut into hundreds of pieces, each piece grows into an independent animal. Such an aggregate of cells may be considered as only a transition step between a Protozoon and a many-celled animal of more highly specialized struc- ture. Hence some naturalists have classed sponges as Protozoa, some make a separate sub-kingdom Porifera, while others class them with the sub-kingdom Coelen-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original work.. French, Nathaniel Stowers, 1854-. New York [etc. etc. ] Longmans, Green and Co

Recherche dans la banque de photos par tags

• bookcentury1900
• bookdecade1900
• booksubjecta
• booksubjectzoology