Keyword Album: Hexabranchus%20sanguineusThis%20species%20of%20very%20large,%20strong-swimming%20nudibranch%20is%20one%20of%20the%20largest%20of%20all%20nudibranchs:%20specimens%20of%20well%20over%2040%20cm%20in%20length%20have%20been%20reported.The%20species%20name,%20sanguineus,%20refers%20to%20its%20bright%20red%20coloration,%20but%20a%20yellow%20variant%20also%20exists.%20This%20nudibranch%20has%20two%20very%20different%20modes%20of%20locomotion:%20crawling%20and%20swimming.%20When%20it%20crawls,%20the%20wide%20edges%20of%20the%20mantle%20(the%20parapodia)%20are%20rolled%20up%20close%20to%20the%20body.%20When%20the%20animal%20swims%20however,%20the%20red%20parapodia%20unfurl,%20and%20are%20whirled%20through%20the%20water%20in%20a%20spectacular%20undulating%20motion,%20propelling%20the%20animal%20forwards.%20The%20animal%20was%20given%20the%20common%20name