Renata Manconi, Barbara Cadeddu, Fabio Ledda, Roberto Pronzato
Zookeys
Figure 19Ircinia variabilis. a–c wide array of growth forms in different specimen d skeletal spongin network of primary and secondary fibres, and filaments (LM) e skeletal spongin network of primary and secondary fibres, and filaments (SEM) f magnification of a filament at the terminal knob; g, h regularly and finely sandy sponge surface. d) modified from Pronzato et al. (2004).