FIGS 18 in Cleavage pattern in Oscarella species (Porifera, Demospongiae, Homoscleromorpha): transmission of maternal cells and symbiotic bacteria

FIGS 18±21. (18) Follicle of the egg of O. imperialis (TEM). Fc, follicular cells; Co, internal layer of collagen; Ba, dividing symbiotic bacteria; Y, yolk granules of the egg. Scale bar: 2 Mm. (19) Vacuolar cells type I (Vc) and symbiotic bacteria (Ba) inside the mesohyl of an adult specimen of O. lobularis (SEM). Scale bar: 5 Mm. (20) Vacuolar cells type I (Vc) and symbiotic bacteria (Ba) inside a cleaving embryos of O. lobularis (SEM). B, blastomeres. Scale bar: 5 Mm. (21) Symbiotic bacteria of two morphological types (BaI, BaII) inside the cleaving embryos of O. lobularis (SEM). B, blastomere. Scale bar: 1 Mm.