What might be a larva of one of the Echinoderm (Sea Urchins). A vertical oval shape, two "arms" descend from the mid part and the top half contains a structure that can be interpreted as eye-like. The image is an anatomical drawing from a possibly 19c text.
https://mastodon.sdf.org/system/media_attachments/files/113/741/729/623/265/992/original/e10521deab8ebe74.png