F. Hemming. 1957. Opinion 468 (Case 875) Addition of the ordinal name Ammonoidea Zittel, 1884 to the Official List of Names in the Order-Class-Group in Zoology, with Arietites Waagen 1869, as type genus. Opinions and Declarations rendered by the ICZN 16(7):89-96 [P. Scofield/P. Scofield]