Microstructure of the shell of Early Triassic ceratites.  Zakharov Yu.  D.-In:Correla-
 tion of Permo-Triassic sediments -of East USSR.  Vladivostok: Far-East Scientific
 Centre, USSR Academy of Sciences, 1986, p. 89-97.

      The results of studing of microstructure of the Early Triassic ammonoid shells
 (Prosphingites, Nordophiceras, Svalbardiceras, Olenikites, Keyserlingites) are discussed
 in the first  time. The ontogenetic acceleration in ammonoid evolution seems to be
 expressed in change of both morphology and microstructure of the shell.