• Webster's Revised Unabridged Dictionary
    • n. pl Pteropoda (Zoöl) A class of Mollusca in which the anterior lobes of the foot are developed in the form of broad, thin, winglike organs, with which they swim at near the surface of the sea.☞ The Pteropoda are divided into two orders: Cymnosomata, which have the body entirely naked and the head distinct from the wings; and Thecosomata, which have a delicate transparent shell of various forms, and the head not distinct from the wings.
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Century Dictionary and Cyclopedia
    • pteropoda A division of Mollusca, having the mesopodium or middle part of the podium or foot expanded into a pair of large alate lobes like wings or flippers, and used as such to swim with; the pteropods. The ctenidia are abortive, the nephridium is single, and the general configuration is more or less unsymmetrical, somewhat as in gastropods. The propodium may be produced into tentaculiform organs. There are otidia or otocysts, and one osphradium. The pteropods are hermaphroditic or monœcious; there are organs of copulation and a single genital pore. According to the presence or absence of a mantle-skirt and shell, the Pteropoda are Thecosomata and Gymnosomata. All are oceanic. They originally formed the second class of Cuvier's branch Mollusca, under the French name Pteropodes. By most conchologists this view has been accepted, but others have united the pteropods with the cephalopods, and still others with the gastropods. By several anatomists they have been approximated to the tectibranchiates, and even supposed to be derived from different stocks of that order — the thecosomes from the Cephalaspidea, and the gymnosomes from the Anaspidea. Also called Coponautæ. See cuts under Cavoliniidæ and Pneumdermon.
    • pteropoda In De Blainville's classification (1825), one of two families of his fifth order, Nucleobranchiata (the other being Nectopoda), composed of the genera Atlanta, Spiratella, and Argonauta. It is thus a highly artificial group, comprising a part of the heteropods together with some cephalopods, etc.
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Webster's Revised Unabridged Dictionary


In literature:

The Pteropoda, formerly regarded as a distinct class of the Mollusca, were interpreted by E.R.
"Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 5" by Various