HMS Myrmidon was a Cormorant-class gunvessel of the Royal Navy, built at Chatham Dockyard and launched in 1867.

She served on the North America and West Indies Station and surveyed parts of the Australian coast before being sold at Hong Kong in 1889.

The first 6 ships had a 2-cylinder horizontal single-expansion steam engine provided by Robert Napier and Sons and rated at 200 nominal horsepower, driving a single screw.

[2] The main armament, which was principally intended for shore bombardment,[3] was originally designed with two 68-pounder and two 32-pounder muzzle-loading smoothbore guns.

[3] The first 6 ships were ordered from commercial yards (Money Wigram & Sons, C J Mare & Co and J Scott Russell).