A Parasitic Flatworm (image) Smithsonian Tropical Research Institute Share Print E-Mail Caption A trematode worm bites and sucks out the insides of an enemy species, with the eyespots of the victim's offspring still visible inside the attacker's gut. At least 20 species of trematode compete to parasitize and castrate marine horn snails (Cerithideopsis species), and such predatory interactions are more frequent in the temperate zone than the tropics. Credit Ryan Hechinger Usage Restrictions Credit: R. Hechinger Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.