. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. INVERTEBRATE BOTTOM FAUNA 463. Fig. 320. Dynamena pumila, L. (After Hincks. Laomedea flexuosa, and Clava squamata (see Fig. 321). There are several bryozoans 1 here too, and the fucoids are often densely thronged by small white spiral-shaped tube-worms (Spirorbis). Amongst the un- attached forms as- sociated with the algae I may mention: Littorina obtusata, which keeps mostly to little bays shel-
. The depths of the ocean; a general account of the modern science of oceanography based largely on the scientific researches of the Norwegian steamer Michael Sars in the North Atlantic. Oceanography. INVERTEBRATE BOTTOM FAUNA 463. Fig. 320. Dynamena pumila, L. (After Hincks. Laomedea flexuosa, and Clava squamata (see Fig. 321). There are several bryozoans 1 here too, and the fucoids are often densely thronged by small white spiral-shaped tube-worms (Spirorbis). Amongst the un- attached forms as- sociated with the algae I may mention: Littorina obtusata, which keeps mostly to little bays shel- tered from the action of the waves ; L. littorea, which is very common; and our smallest shelled snail Skene a planorbis, which is met with in favoured spots under stones and upon algae of different species. More local in their occurrence, though generally numerous where found, are certain species of Actiniae—the red Actinia equina (see Fig. 322), the yellow or brownish Metridium dianthus (see Fig. 323), and Urticina crassicornis being the commonest forms. The first of these is generally found in quiet bays where the shore is covered with large stones and pebbles, the individuals being sometimes attached to these and sometimes to cracks in the rock. As this species produces its young fully developed, and the newly-born actiniae are able to attach themselves easily, it is frequently met with in fairly large colonies. Another remarkable mode of propaga- tion, namely schizogony, is to be seen in Metridium dianthus in its younger stages. From the foot-disc of the animal small pieces unwind and form new organs, such as new tentacles, new mouth, etc. In this way colonies are formed, which may be widely distributed over the rock or the roots of the laminaria. 1 Chiefly Alcyonidium hirsutum, Flustrella hispida, Bowerbankia Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance
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