203
Fig. 2.47 Schematic longitudinal sections of brooding zooids with
internal brood sacs in: ( A ) Cryptosula pallasiana ; ( B ) Watersipora
subtorquata . Abbreviations: as ascus, bs brood sac, bsw brood-sac wall,
bw basal wall, bz brooding zooid, dz distal zooid, fr frontal shield,
hc hypostegal coelom, i introvert, m muscle strands of brood sac, op
operculum, tw transverse wall
Figures