The results of the study of ontogenetic transformations of the sculpture and shape of ammonite shells of the genus Cranocephalites Spath, 1932 from the Yuryung-Tumus Peninsula are presented. These results are compared with data on the ontogenies of the representatives of genera Arctocephalites Spath, 1928 and Arcticoceras Spath, 1924. It has been established that Cranocephalites clearly differs from Arcticoceras starting from the second half of the fourth and to the beginning of the fifth whorl. Cranocephalites differs from Arctocephalites at the late stages of ontogeny, and this raises the question of the legitimacy of distinguishing the Cranocephalites as a separate genus.