silhouettes of aeolid nudibranch and dorid nudibranch.

blue silhouette doridoidea shell-less marine gastropod mollusks doridacea nudibranchia nudibranchs slug mollusk mollusc sea invertebrates gastropods nudibranch animal background fauna isolated marine molluscs rhinophores sea vector white wild wildlife underwater aeolid aeolid aeolidida cerata external parapodial tentacles