"Male of Argonauta showing "hectocotylus" arm." -Thomson, 1916

Argonauta

"Male of Argonauta showing "hectocotylus" arm." -Thomson, 1916

"Hectocotylus of Tremoctopus violaceus." — Encyclopedia Britannica, 1893

Hectocotylus

"Hectocotylus of Tremoctopus violaceus." — Encyclopedia Britannica, 1893