Holochoanitic

Other Early Paleozoic cephalopods have holochoanitic siphuncles

He accepted the Plectronoceratidae as primitive, and the Ellesmeroceratidae as the derived next step, one characterized by holochoanitic structure and diaphragms, and leading to a group of endoceroids;

However, over a short period of time (less than 10 Ma) during the late Devonian, the Clymeniida developed a dorsal (or internal) holochoanitic siphon.