. Animal life as affected by the natural conditions of existence. Animal ecology. A COBAL AND A MOLLUSC. 337 they are perfectly constant—no specimen having hitherto been found without such holes, suiEciently proving that a Sipunculus lives as commensal in the coral—they here hear the asjiect, or disguise, of a true specific character. Many years since, a very interesting case of association or commensalism between a mollusc and a coral was described by Steenstrup. The young of Rhizochilus antipathum (see fig. 88) have all the appearance and characters of a true Buccinum. When they have reached
. Animal life as affected by the natural conditions of existence. Animal ecology. A COBAL AND A MOLLUSC. 337 they are perfectly constant—no specimen having hitherto been found without such holes, suiEciently proving that a Sipunculus lives as commensal in the coral—they here hear the asjiect, or disguise, of a true specific character. Many years since, a very interesting case of association or commensalism between a mollusc and a coral was described by Steenstrup. The young of Rhizochilus antipathum (see fig. 88) have all the appearance and characters of a true Buccinum. When they have reached a certain size they attach themselves to the slender branches of a horny coral known as Antipathes, and at once so modify their normal growth that it is quite impossi- ble to name any other mollusc in which any alterations of growth at maturity are to be met with in the least resembling. Fig. 88.—Rldzochihts antipathum, Steenstnip. To the right the young shell exactly resembling Buccinum • to the left the old shell firmly attached to the branches of Anti- pathes by its irregularly formed margin. it. The shell throws out processes in every direction, by which it clings to. the coral, in the mode here shown in a woodcut copied from Steenstrup, till at last the mollusc loses all power of motion and lies, anchored as it were, to the Anti- pathes. Of what use this can be to the animal it is difficult to say; but we may venture to put forward the hypothesis that it must be, and is, of some service, and also that an originally accidental connection and growth of some true species of Buc- cinum with the slender branches of a Gorgonia must have given rise to this extraordinary habit. Certain parasitic Crustaceans offer another example of such a peculiar action of one animal on another. The species of Pel- togaster often live attached to the hind pai-t of the body of the hermit crab, and they then assume the form necessitated by that. Please note that these images are extracted
Size: 1576px × 1585px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, bookpublishernewyo, bookyear1881
