(Clypeaster rosaceus, by Ernst Haeckel, Kunstformen der Natur, 1904)
I spent the better part of an entire chapter of DEEP BLUE HOME describing the fascinatingly complex life history of jellyfish. Here's a lovely short film from the Brazil's Centro de Biologia Marinha, Universidade de Sao Paulo, telling a similar story for the Caribbean sea biscuit, Clypeaster rosaceus, a sand dollarlike echinoderm.
The film circumvents language to deliver an elegant lesson on one of nature's most economic solutions to dispersing sessile organisms in the ocean.
HT The Artful Amoeba.