<i>Sipunculus nudus</i>. A species of unsegmented marine worm, commonly called the peanut worm. "B, Larval Sipunculus, about one twelfth of an inch long. o, mouth; oe, esophagus; s, caecal gland; i1, intestine with masses of fatty cells; a, anus; w, ciliated groove of intestine; g, brain with two pairs of red eye-spots; n, nervous cord; p, pore; t, t1, so-called testes; W, W, circlet of cilia." &mdash;Whitney, 1889

Peanut Worm - Interior Anatomy of Larva

Sipunculus nudus. A species of unsegmented marine worm, commonly called the peanut worm. "B, Larval…