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pluteus
[ ploo-tee-uhs ]
noun
- the free-swimming, bilaterally symmetrical larva of an echinoid or ophiuroid.
Other Words From
- plute·al plute·an adjective
Word History and Origins
Origin of pluteus1
Example Sentences
Pluteus, a free-swimming larval stage in the development of echinoderms, 54.
In these early stages the young, or the so-called larvæ of Echinoderms, have received the name of Pluteus on account of their ever-changing forms.
The appearance of the Sea-urchin, as soon as this larva or Pluteus is completely absorbed, is much more like that of the adult than is the Star-fish at the same stages, in which, as we have seen, there is a transition period of considerable duration.
By the limestone rods which support the arms, the Pluteus of the Ophiuran, here represented, resembles that of the Sea-urchin more than that of the Star-Fish, while by the character of the water-tubes and by its internal organization it is more closely allied to the latter.
It differs from both, however, in the immense length of two of the arms; these arms being the last signs of its plutean condition to disappear; when the young Ophiuran has absorbed almost the whole Pluteus, it still goes wandering about with these two immense appendages, which finally share the fate of all the rest.
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