Skip to main content
Fig. 7 | BMC Ecology and Evolution

Fig. 7

From: Three in one: evolution of viviparity, coenocytic placenta and polyembryony in cyclostome bryozoans

Fig. 7

Details of gonozooid ultrastructure in Crisiella producta (ad, f) and Crisia eburnea (e, g) (TEM). a ‘Mesothelial’ cell connecting epithelium of the cystid wall and non-altered membranous sac (here and elsewhere basal lamina of the membranous sac shown by arrowheads). b Interzooidal wall (autozooid to the left) with communication pore plugged by a pore-cell, and ‘mesothelial’ cells connected with cystid epithelium and membranous sac. c Processes of ‘mesothelial’ cells passing through basal lamina (asterisks) and contacting binucleate cell of membranous sac; d ‘Mesothelial’ cell adjacent to basal lamina of former membranous sac (short process of the nutritive tissue piercing it and contacting ‘mesothelial’ cell indicated by white arrow). e Presumed pseudocoelomocyte in the pseudocoel. f Interzooidal wall between autozooid (to the left) and gonozooid with communication pore plugged by two pore-cells (one of them contacting ‘mesothelial’ cells). g Wall of gonozooid with two mural spines (arrows). c, coelom; cu, cuticle; cw, organic matrix of calcified wall; e, early secondary embryo; ep, epidermal lining of cystid walls; g, gut of autozooid; iw, interzooidal wall; mc, ‘mesothelial’ cell; ms, membranous sac; nt, nutritive tissue; pc, pseudocoel; pg (1 & 2), pore-cells plugging communication pore; sc, storage cells; uc, ‘upper cell complex’

Back to article page