Аннотация:The radula of gastropods is a unique structure of the feeding apparatus, whichis characterized by its incredible morphological diversity. The radula consists of the teethattached to the radular membrane and is formed by specialized cells in the radular sac. Themode of the radula formation, including the type of secretion, the number, size, and shapeof the cells forming one tooth, can vary significantly between different mollusks. Clarifi-cation of this diversity is the key to determining the patterns of radula formation inGastropoda. Thegeneralmorphologyandultrastructureofradulaof Clione limacina(Gastropoda:Pteropoda)wasstudiedusinglight,electron,andconfocallaserscanningmicroscopyforthefirsttime.Theradulaformulaisn1nwithwidecentraltoothandhook-likelateralteeth(from7to12).TheuniquefeaturefortheGymnosomataistheincreasingsizeandnumberofteethduringthelifeoftheanimal,possibly,duetotheuniquepositionofodontoblasts,locatedontheperipheryoftheblindendoftheradularsac.Theultrastructureof C. limacina combinesfeaturesandcharacteristicsthataretypicalforallHeterobranchia.Ultrastructureoftheformationzone(cellsintheformationzonewithpoordifferentiation),structureofradularmembrane,andabsenceofsubradularmembranearecharacteristicfor C. limacina.Themodeoftoothformation(onetoothis formed byseveralodontoblastsandmicrovillarsecretion),radularbolsters,andmuscularmorphologyaresimilartootherHeterobranchia.Thefirmconnectionbetweenradulaandradularbolsterwithoutasubradularmembrane,themuscularradularsupportstructure,whichgivesadditionalmobilitytotheradula,andmuscleswhichconnecthooksacscouldindicateasignificantcontributionoftheradulatoscrapingtheprey. As a result of this study, theultrastructure of the radular apparatus of one species Gymnosomata was described for thefirst time. These data significantly extend our knowledge of the gastropods radulaformation