ABSTRACT.  The writer discusses the problem, suggested by some authors, of
interpretation of small forms in Ammonoidea as neotenic ones.  The classical conception
of neoteny is connected with presence of a larval stage which in Arnmonoidea was very tiny.
It therefore appears that small forms in Ammonoidea are highly advanced in their ontogenetic
development als compared with a larval stage of this group. Numerous examples are also
known of the dimorphism, the large and small forms in which differ in their dimensions very
indistinctly.  The latter facts contradict a conception of a neotenic character of small forms.
The writer discusses also the problem of systematics of the Ammonoidea against the
background of the commonly being accepted theory of sexual dimorphism.