Abstract.   The early internal shell features in 40 species of the Goniatitida, Prolecanitida and
    Ceratitida are described on the basis of well-preserved specimens from the Carboniferous and the
    Permian of North America, England, Siberia and Urals.  Seven morphotypes were recognized in the
    species examined by differences of the caecum shape (bottle-shaped, gourd-shaped, subelliptical,
    or elliptical), the proseptum length on the dorsal side (long or short), position of the second septum
    (close to proseptum or not) and initial position of the siphunele (ventral, subcentral, or central).
    Paraceltites elegans, the oldest known representative of the Ceratitida, has a long proseptum on
    the dorsal side, a relatively small ammonitella angle, the second septum does not appear in close
    vicinity to proseptum, and the siphuncle is ventral.  These features are essentially the same es
    those of the prolecanitid Daraelites elegans.  This fact supports the hypothesis that the Ceratitida
    evolved from the Prolecanitida, probably Daraelites.

    Key words: Ceratitida, early internal shell features, Goniatitida, phylogeny, Prolecanitida