What is "hectocotyli"

Hectocotylus \Hec`to*cot"y*lus\, n.; pl. Hectocotyli. [NL., fr. Gr. ? a hundred + ? a hollow vessel.] (Zo["o]l.) 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.

n. (plural of hectocotylus English)

See hectocotylus