Abstract: The external structure and solutable proteins of chorion were studied compara-tively in amphimictic fish,i.e. red goldfish,Carassius aaratus red variety and colo-ured goldfish, Carassius aaratus coloured variety,and gynogenetic crucian carp,Ca-rassius auratus gibelio.The chorion surface was smoother in gynogenetic cruciancarp than those in amphimictic fish.That is,the ridge and ditch on chorion wereunclear in crucian carp.Contents of solutable proteins in chorion of gynogeneticcrucian carp were slightly higher than in amphimictic fish, and electrophoreticpattern of chorion in crucian carp was characteristic of a protein band in districtII with molecular weight of 105 dalton.The structure and composition of chorionwere discussed in relation to the primary control of crucian carp eggs.