. Animal studies. COMMENSALISM AND PARASITISM 337 r 271. Symbiosis.—Of a more intimate character, and of more obvious and certain mutual advantage, is the well- known association called symbiosis. The hermit-crab always takes for his habitation the shell of another animal, often that of the common whelk. All of the hind part of the crab lies inside the shell, while its head with its great claws project from the opening of the shell. On the surface of the shell near the opening there is often to be found a sea-anemone, or sea-rose (Fig. 203). This sea-anemone is fastened securely to the shell,
. Animal studies. COMMENSALISM AND PARASITISM 337 r 271. Symbiosis.—Of a more intimate character, and of more obvious and certain mutual advantage, is the well- known association called symbiosis. The hermit-crab always takes for his habitation the shell of another animal, often that of the common whelk. All of the hind part of the crab lies inside the shell, while its head with its great claws project from the opening of the shell. On the surface of the shell near the opening there is often to be found a sea-anemone, or sea-rose (Fig. 203). This sea-anemone is fastened securely to the shell, and has its mouth opening and tentacles near the head of the crab. The sea-anemone is carried from place to place by the hermit-crab, and in this way is much aided in obtain- ing food. On the other hand, the crab is protected from its enemies by the well-armed and dangerous tentacles of the sea-anemone. If the sea- anemone be torn away from the shell inhabited by one of these crabs, the crab will wan- der about, carefully seeking for another anemone. When he finds it he struggles to loosen it from its rock or from whatever it may be growing on, and does not rest until he has torn it loose and placed it on his shell. There are numerous small crabs called pea-crabs (Pin-. Fig. 202.—A Portuguese man-of-war (Physalia), with man-of-war fishes (Nomeus gronovii) living in the shelter of the stinging feelers. Specimens from off Tampa, 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 Jordan, David Starr, 1851-1931; Kellogg, Vernon L. [from old catalog].
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Keywords: ., bookauthorjordanda, bookcentury1900, bookdecade1900, bookyear1903
