My favorite is his drawing of a eurypterid / sea scorpion.    From Wordnik.com.  [Luskin, Haeckel, Richardson, Richards - The Panda's Thumb] Reference

This paper, with Hünicken as a coauthor, revises the identity of this fossil as a “bizarre eurypterid”, a water scorpion Eurypterida.    From Wordnik.com.  [Archive 2006-02-01] Reference

What all this summons into my mind, as I continue the path of free association from T.S. Eliot through my eurypterid to Rhyniognatha, is H.P. Lovecraft's splendid novella, "At the Mountains of Madness" (1936), one of his few genuine science-fiction stories, and a dazzling one.    From Wordnik.com.  [Asimov's Science Fiction]

It is the largest known walking trackway of a eurypterid or any invertebrate animal.    From Wordnik.com.  [BBC News | News Front Page | World Edition] Reference

The discovery is the largest known walking trackway of a eurypterid or any invertebrate animal.    From Wordnik.com.  [Telegraph.co.uk: news, business, sport, the Daily Telegraph newspaper, Sunday Telegraph] Reference

Gradually the antique types of the Paleozoic fauna died out, and in the Permian rocks are found the last survivors of the cystoid, the trilobite, and the eurypterid, and of many long-lived families of brachiopods, mollusks, and other invertebrates.    From Wordnik.com.  [The Elements of Geology] Reference