200
Fig. 2.44 Schematic longitudinal sections of hyperstomial ovicells in:
( A ) Microporella ciliata (ovicell acleithral); ( B ) Pacifi cincola insculpta
(ovicell subcleithral). Abbreviations: as ascus, av avicularium, bc brood
cavity, bcw brood-cavity wall, bw basal wall, dz distal zooid, ес ectooecium, en entooecium, fe fertilization envelope, fr frontal shield,
hc hypostegal coelom, i introvert, m muscle strands of ooecial vesicle,
mz maternal zooid, ос ooecial coelom, of ovicell fl oor, op operculum,
os oral spine, tw transverse wall, v ooecial vesicle
2 Cheilostome Brood Chambers: Structure, Formation, Evolution
Fig. 2.44 Schematic longitudinal sections of hyperstomial ovicells in:
( A ) Microporella ciliata (ovicell acleithral); ( B ) Pacifi cincola insculpta
(ovicell subcleithral). Abbreviations: as ascus, av avicularium, bc brood
cavity, bcw brood-cavity wall, bw basal wall, dz distal zooid, ес ectooecium, en entooecium, fe fertilization envelope, fr frontal shield,
hc hypostegal coelom, i introvert, m muscle strands of ooecial vesicle,
mz maternal zooid, ос ooecial coelom, of ovicell fl oor, op operculum,
os oral spine, tw transverse wall, v ooecial vesicle
2 Cheilostome Brood Chambers: Structure, Formation, Evolution