Seahorse (also written sea-horse and sea horse) is the name given to 46 species of small marine fish in the genus Hippocampus. "Hippocampus" comes from the Ancient Greek hippokampos (ἱππόκαμπος hippókampos), itself from hippos (ἵππος híppos) meaning "horse" and kampos (κάμπος kámpos) meaning "sea monster". Having a head and neck suggestive of a horse, seahorses also feature segmented bony armour, an upright posture and a curled prehensile tail. Along with the pipefishes and seadragons (Phycodurus and Phyllopteryx) they form the family Syngnathidae.