hectocotylus

Hec`to*cot"y*lus, n.; pl. Hectocotyli. Etym: [NL., fr. Gr. (Zoöl.) Defn: 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.

---