. Economic mollusca of Acadia . Fig. 22.— Teredo navalis. Twice Natural Size. or other obstruction. They never pierce each other's tubes. As the latter are formed, they are lined by a calcareous layer, more or less- thick, and firm enough to allow large pieces of it to be removed entire from the wood after the animal is dead. It is still doubtful what mechanism the animal employs in burrowing. Many naturalists think the valves, armed bj' numerous fine constantly growing teeth, form the apparatus, and that by them the animal eats, or rather files, its way onward. One observer states, that by br
. Economic mollusca of Acadia . Fig. 22.— Teredo navalis. Twice Natural Size. or other obstruction. They never pierce each other's tubes. As the latter are formed, they are lined by a calcareous layer, more or less- thick, and firm enough to allow large pieces of it to be removed entire from the wood after the animal is dead. It is still doubtful what mechanism the animal employs in burrowing. Many naturalists think the valves, armed bj' numerous fine constantly growing teeth, form the apparatus, and that by them the animal eats, or rather files, its way onward. One observer states, that by breaking away the side of a burrow, he has actually seen this operation going on; others claim that the foot accomplishes the work, by the same unknown means by which certain limpets can excavate rocks. It is pretty generally agreed, how- ever, that the Teredos do not get nourishment from the wood, but bore- it simply to form a home. Their food consists of minute animals and. plants, taken into the body through one of the siphons.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectmollusks, bookyear188
