Starfish in military history. Three ships of the Royal Navy have borne the name "HMS Starfish": an A-class destroyer launched in 1894; an R-class destroyer launched in 1916; and an S-class submarine launched in 1933 and lost in 1940. In the World War II, Starfish sites were large-scale night-time decoys created during The Blitz to simulate burning British cities. Starfish Prime was a high-altitude nuclear test conducted by the United States on 9 July 1962. Starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are
Invertebrate the Nemertea or ribbon worms, and the Sipuncula. Another phylum is Platyhelminthes, the flatworms. These were originally considered primitive, but it now appears they developed from more complex ancestors. Flatworms are acoelomates, lacking a body cavity, as are their closest relatives, the microscopic Gastrotricha. The Rotifera or rotifers, are common in aqueous environments. Invertebrates also include the Acanthocephala or spiny-headed worms, the Gnathostomulida, Micrognathozoa, and the Cycliophora. Also included are two of the most successful animal phyla, the Mollusca and Annelida. The former, which is the second-largest animal phylum by number of described species, includes animals such as snails, clams,