Beautiful, swimming flatworm.
Gusano NO segmentado,
One of several flatworms, all looking like this, that we found under rocks in the intertidal zone. This one was with a chiton.
You can see its primitive eyes clearly, especially on the third photo.
The flatworms, known in scientific literature as Platyhelminthes or Plathelminthes (from the Greek πλατύ, platy, meaning "flat" and ἕλμινς (root: ἑλμινθ-), helminth-, meaning worm) are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrate animals. Unlike other bilaterians, they have no body cavity, and no specialized circulatory and respiratory organs, which restricts them to having flattened shapes that allow oxygen and nutrients to pass through their bodies by diffusion. The digestive cavity has only one opening...