Pseudorthocerids and actinocerids ( respectively Pseuorthocerida and Actinocerida ) are organic cephalopods , generally with long straight shells and expanded siphuncle segments filled with extinct nautiloid deposits .
Pseudorthocerids and actinocerids ( respectively Pseuorthocerida and Actinocerida ) are extinct nautiloid cephalopods , generally with long straight shells and expanded siphuncle segments filled with organic deposits .