Male of Ocythoe tuberculata Raf. (=Philonexis catenulatus, Fer.), Mediterranean, showing three stages, A, B, and C., in the development of the hectocotylus arm; h.cy, hectocotylus still in the cyst; c'y', spoon-shaped cyst at the end of the arm when freed; th, thread-like organ freed by the rupture of c'y'....
The Cephalopod. atlasJerusalem :Israel Program for Scientific Translations ; Springfield, Va. : available from the U. S. National Technical Information Service,1975.biodiversitylibrary.org/page/32124297