Periophthalmus
a genus of Gobiidæ, from the coasts of the Indo- Pacific, remarkable for their prominent retractile eyes, which enable them to see in the air as well as in the water, and for their strong ventral and pectoral fins, by the aid of which they can hop freely over the ground, when they leave the water, as is their habit at ebb tide, to hunt small crustaceans. The species are few in number; but P. koelreuteri is one of the commonest fishes of the Indian Ocean.