The nature and origin of the cortical morphogenetic field in Limnaea

[摘要] ThevegetativepoleplasminrecentlylaideggcellsofLimnaeastagnalisissituatedsomewhatobliquelywithrespecttothelongitudinalaxisofthefirstmaturationspindle.Intheequatorialzoneoftheeggtherearesixsubcortical“patches”ofcytoplasmstainingdifferentlyfromthesurroundingcytoplasm.Theyarearrangedaccordingtoanasymmetricpattern.Thesecytoplasmicdifferentiationsoftheovipositedeggarisebyooplasmicsegregationduringthepassageoftheeggcellthroughthefemalegenitalductoftheparent.Theypointtoapreexistentmosaicpatterninthecortex,whichisatthesametimepolar,dorsoventral,andasymmetric.Thegrowingoocytesinthegonadliewithonesideflatagainsttheacinuswall.Theyaresurroundedbysixinnerfolliclecellsinacharacteristicarrangement.Theoocytewithitssurroundingstructuresalsoembodiesapatternwhichisatthesametimepolar,dorsoventral,andasymmetric.Thepatternsoftheeggfollicleandoftheovipositedeggshowagreatdealofsimilarity.Itisconcludedthatthemosaicpatternofthecortexofthefertilizedeggcellreflectspeculiaritiesinthemutualpositionsofelementssurroundingtheoocyte.

[学科分类] 生物科学（综合）