Fig. 2

Longitudinal optical section of cnidosac in different Fionidae species (CLSM). A Eubranchus rupium; B Cuthonella hiemalis; C Cuthona nana; D Zelentia pustulata, proximal end of cnidosac is not seen due to its large size, white dotted lines indicate cnidophages, yellow dotted line indicates NCs layer; E Diaphoreolis viridis, white dotted lines in cnidosac indicate cnidophages, white dotted lines in haemocoel indicates cells with chitinous elements; F Catriona columbiana, proximal end of cnidosac is not seen due to its large size. cnph cnidophage, cns cnidosac, cp cnidopore, dg digestive gland, ep epithelium, hc haemocoel cells with chitinous spindles, he haemocoel, mb body musculature, mc cnidosac musculature. White arrowheads indicate cellules speciale, star—cnidosac entrance (where applicable). Scale bars: 20 µm