Horn Snails (IMAGE) Smithsonian Tropical Research Institute Caption The Pacific horn snail (Cerithideopsis californica) and Atlantic horn snail (C. pliculosa) are two closely related species found in estuaries along the coasts from the tropics up into the temperate zone. Since they are broadly distributed across varying habitats, and host several species of parasitic flatworms under their shells, these snails provide scientists with an ideal opportunity to study questions about how diversity changes with latitude. Credit STRI/Sean Mattson Usage Restrictions credit: STRI License Licensed content 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.