To replace supposedly preoccupied Cryptosaurus Seeley,1869. Lydekker's citation of "Cryptosaurus geoffroy" is based on a typographical error for Cystosaurus geoffroy 1833 in a German journal, an error repeated by Agassiz in his 1846 Nomenclator Zoologicus. Such incorrect subsequent spellings are not a basis for homonymy under ICZN rules. Cryptosaurus eumerus = Cryptodraco Lydekker's renaming of Cryptosaurus to Cryptodraco was unjustified.