Turbellarian taxonomic database

Catenulida Retronectidae


without paratomy;
without cilated pits or furrows;
without refractile bodies;
brain with 2 posterior and 2-5 anterior gangliar lobes;
mixed gonads elongated, usually hourglass-shaped, most in male condition;
sometimes posterior part of gonad develops into an ovary;
sperm nucleus usually of very distinctive shape (conglomerate, rod-, ribbon-, spicule-, banana-shaped);
paired granular strands of parenchymous nature usually present between gut and skin;
generally with statocyst with 4 nuclei in ventral wall;
marine.