Hippocampus

[T]hen all collapsed, and the great shroud of the sea rolled on as it rolled five thousand years ago.
~Herman Melville

We have a mix of hippocamps (Greek mythological horse-fish) and seahorses today. On the New Page Books blog, Oberon Zell-Ravenheart writes that in medieval times "it was believed that all creatures of the land had their aquatic counterparts in the sea, often distinguished by little more than fins instead of legs. Thus our marine menagerie is enriched by such wonders as Mermaids (meaning “Sea-maids”), Sea-Lions, Sea-Unicorns (Narwhals), Sea-Dogs (dogfish sharks), Sea-Cats (catfish), Sea-Bats, Sea-Anemones, Sea-Cucumbers, Sea-Hares, Sea-Goats (Capricorn), Angel-Fish, Devil-Fish, Ichthyocentaurs (“Fish-Centaurs”), Rooster-Fish, Sea-Elephants, Sea-Serpents—and Sea-Horses."

The Latin genus name for seahorses is "hippocampus" ("sea monster horse"). You might have heard of the part of the brain known as the hippocampus, so named for its shape, which vaguely resembles a seahorse.

Ausblick von der Terrasse
photo by Alexander Gerzabek

Riding in Silence
photo by André P. Meyer-Vitali

Rome - "Trevi Fountain - Triton & Seahorse"
photo by David Ohmer

Weedy Sea Dragon
photo by Images by John K

Seahorse
photo by エン バルドマン

Seahorse
photo by Darren Larson

Pacific Seahorse
photo by Peter Liu

Caballito de mar
photo by FGE Pascalteco

Hippocamps
by Walter Crane

Origami Winged Seahorse
by Daniel Chang

Links:

* The Seahorse Trust
* Zoological Society of London's Project Seahorse
* A Canadian Project Seahorse
* Seahorses: A race against habitat destruction