from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A modified arm of the male of certain cephalopods, such as the octopus, functioning as a reproductive organ in the transference of sperm to the mantle cavity of the female.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A modified arm of any of several male cephalopods that functions as a reproductive organ by transfering sperm to the mantle of the female

from the GNU version of the Collaborative International Dictionary of English

  • n. One of the arms of the male of most kinds of cephalopods, which is specially modified in various ways to effect the fertilization of the eggs. In a special sense, the greatly modified arm of Argonauta and allied genera, which, after receiving the spermatophores, becomes detached from the male, and attaches itself to the female for reproductive purposes.

from The Century Dictionary and Cyclopedia

  • n. [capitalized] In zoology, a spurious genus of parasitic organisms, the same as the Trichocephalus of Delle Chiaje; in reality, the detached male arm of a cephalopod, attached to the female, and mistaken for a parasite.
  • n. In biology, the metamorphosed reproductive arm of certain of the male cephalopods, as the argonaut, which becomes detached and is deposited within the mantle-cavity of the female for the purpose of conveying the sperm-cells to her. Also hectocotyle. See cut under Argonautidæ.


New Latin : hecto- + Greek kotulē, small cup.
(American Heritage® Dictionary of the English Language, Fourth Edition)


  • The male octopus uses a specialized arm called a hectocotylus to transfer sperm to the mantle cavity of a receptive... perhaps the monsters in Cloverfield "bite" humans and inject their mutated sperm into humans who then explode with baby monster squids soon thereafter?

    Monstrous Poster - High Res

  • However, the common barnacle, has the longest penis in relation to the size of its body, - up to ten times the height of the barnacle when extended. octopus uses an arm (the third on the right, called the hectocotylus) as its penis.

    Citizendium, the Citizens' Compendium - Recent changes [en]

  • In some species, they have an arm called hectocotylus is used to transfer spermatophore to the females.

    CreationWiki - Recent changes [en]

  • Most of species, they have an arm called hectocotylus is used to transfer spermatophore to the females.

    CreationWiki - Recent changes [en]

  • The male argonaut produces a ball of spermatozoa in a special tentacle called a hectocotylus [wiki].


  • The adapted tentacle has kept the 'hectocotylus' tag, but this is one example when a direct reading of Aristotle really would have trumped what was then modern science...

    "Let them learn Latin"

  • Now, there’s plenty of evidence that Aristotle didn’t gather all those data on his own – HA in particular is full of references to other authors (‘Ctesias says this about the sperm of the elephant’ &c.) and animal handlers (the bit about the hectocotylus came from fishermen, for example).

    "Let them learn Latin"


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