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Fig. 2.40 Ovicell formation in Porella smitti . ( A ) Peripheral part of
non-cleaned air-dried colony with developing ovicells. ( B ) Part of
cleaned colony with fully formed ooecia ( arrow indicates fused ooecia). ( C , E ) Peripheral zooids with developing frontal shield and
ooecium (early stage of ovicell-fl oor calcifi cation in the form of a
bilobate plate; arrow indicates developing communication pore of
ooecium). ( D ) Earliest stage of ooecial-fold formation (lobes of
developing frontal shield grow towards each other beneath the ovicell fl oor). ( F ) Double-disk stage (non-cleaned specimen); inset ,
edge of non-cleaned ooecial fold starting to overgrow frontal surface of distal zooid. Abbreviations: av suboral avicularium, cr cryptocyst, dz distal zooid, ес ectooecium, en entooecium, mz maternal
zooid, op operculum, os oral spine. Scale bars: A – D , F , 100 μm; E ,
inset , 10 μm
2 Cheilostome Brood Chambers: Structure, Formation, Evolution
Fig. 2.40 Ovicell formation in Porella smitti . ( A ) Peripheral part of
non-cleaned air-dried colony with developing ovicells. ( B ) Part of
cleaned colony with fully formed ooecia ( arrow indicates fused ooecia). ( C , E ) Peripheral zooids with developing frontal shield and
ooecium (early stage of ovicell-fl oor calcifi cation in the form of a
bilobate plate; arrow indicates developing communication pore of
ooecium). ( D ) Earliest stage of ooecial-fold formation (lobes of
developing frontal shield grow towards each other beneath the ovicell fl oor). ( F ) Double-disk stage (non-cleaned specimen); inset ,
edge of non-cleaned ooecial fold starting to overgrow frontal surface of distal zooid. Abbreviations: av suboral avicularium, cr cryptocyst, dz distal zooid, ес ectooecium, en entooecium, mz maternal
zooid, op operculum, os oral spine. Scale bars: A – D , F , 100 μm; E ,
inset , 10 μm
2 Cheilostome Brood Chambers: Structure, Formation, Evolution