Kullmann, J. & Scheuch, J.: Wachstums-Änderungen in der Ontogenese
 paläozoischer Ammonoideen. [Growth Changes in the Ontogeny of Paleozoic
 Ammonoids.]--  [Konstruktions-Morphologie Nr. 2.]
Lethaia, Vol. 3, pp. 397-412.  Oslo, October 15th, 1970.
 
Ontogenetic allometries (heterauxesis according to Huxley) of about 50 Carboniferous goniatite
species from Germany, Spain and USA have been studied by means of geometrical measurements
of shell cross sections. They indicate changes of proportions during ontogeny between coiling
spiral, umbilical spiral, and whorl width.  The allometry constants change suddenly at defined stages.
Thus the ontogenetic growth pattern is polyphase, each phase being determined by a different
allometric formula.