The flesh of some fishes is at times, or constantly, _poisonous_. When eaten, it causes symptoms of more or less intense irritation of the stomach and intestines, inflammation of the mucous membranes, and not rarely death. The fishes, the flesh of which appears always to have poisonous properties, are _Clupea thrissa_, _Clupea venenosa_, and some species of _Scarus_, _Tetrodon_, and _Diodon_. There are many others which have occasionally or frequently caused symptoms of poisoning. Poey enumerates not less than seventy-two different kinds from Cuba; and various species of _Sphyræna_, _Balistes_, _Ostracion_, _Caranx_, _Lachnolæmus_, _Tetragonurus_, _Thynnus_, have been found to be poisonous in all seas between the tropics. All or nearly all these fishes acquire their poisonous properties from their food which consists of poisonous Medusæ, Corals, or decomposing substances. Frequently the fishes are found to be eatable if the head and intestines be removed immediately after capture. In the West Indies it has been ascertained that all the fishes living and feeding on certain coral banks are poisonous. In other fishes the poisonous properties are developed at certain seasons of the year only, especially the season of propagation: as the Barbel, Pike, and Burbot, whose roe causes violent diarrhœas when eaten during the season of spawning. * * * * * [Illustration: Fig. 98.--Portion of tail, with spines, of _Aëtobatis narinari_, a Sting-ray from the Indian Ocean. _a_, nat. size.]