178
Fig. 2.20 Reconstruction of early ovicellogenesis in calloporids in the
absence ( A – C ) and presence ( D – F ) of an adventitious avicularium (outer
calcifi cation black , underlying calcifi cation dotted , arrowheads showing growth directions, ooecial communication canal and pores shown
by dotted lines ) (From Ostrovsky et al. 2003 , courtesy of Elsevier,
http://www.sciencedirect.com/science/article/pii/S0044523104701047 ).
Abbreviations: av avicularium, cr cryptocyst, fm frontal membranous
wall, fo ooecial fold, of ovicell fl oor, ор operculum, tw transverse wall,
v ooecial vesicle, vw vertical wall between coelomic cavities of ooecium
and avicularium
2 Cheilostome Brood Chambers: Structure, Formation, Evolution
Fig. 2.20 Reconstruction of early ovicellogenesis in calloporids in the
absence ( A – C ) and presence ( D – F ) of an adventitious avicularium (outer
calcifi cation black , underlying calcifi cation dotted , arrowheads showing growth directions, ooecial communication canal and pores shown
by dotted lines ) (From Ostrovsky et al. 2003 , courtesy of Elsevier,
http://www.sciencedirect.com/science/article/pii/S0044523104701047 ).
Abbreviations: av avicularium, cr cryptocyst, fm frontal membranous
wall, fo ooecial fold, of ovicell fl oor, ор operculum, tw transverse wall,
v ooecial vesicle, vw vertical wall between coelomic cavities of ooecium
and avicularium
2 Cheilostome Brood Chambers: Structure, Formation, Evolution