Milne-Edwards found this observation perfectly correct, for, wishing to place some living pholades in alcohol, he saw a luminous matter exude from their bodies, which, on account of its weight, sank in the liquid, covering the bottom of the vessel, and there forming a deposit as shining as when it was in contact with the air. Several kinds of fishes likewise possess the luminous faculty. The sunfish, that strange deformity emits a phosphoric gleam; and a species of Gunard (_Trigla lucerna_) is said to sparkle in the night, so as to form fiery streams through the water. With regard to the luminosity of the larger marine animals, Ermann, however, remarks that he so often saw small luminous crustacea in the abdominal cavity of the transparent _Salpa pinnata_ that it may well be asked whether the phosphorescence of the larger creatures is not in reality owing to that of their smaller companions. According to Mr. Bennett--_Whaling Voyage Round the Globe_--a species of shark first discovered by himself is distinguished by an uncommonly strong emission of light. When the specimen, taken at night, was removed into a dark apartment, it afforded a very interesting spectacle. The entire inferior surface of the body and head emitted a vivid and greenish phosphorescent gleam, imparting to the creature by its own light a truly ghastly and terrific appearance. The luminous effect was constant, and not perceptibly increased by agitation or friction. When the shark expired (which was not until it had been out of the water more than three hours), the luminous appearance faded entirely from the abdomen, and more gradually from other parts, lingering longest around the jaws and on the fins. The only part of the under surface of the animal which was free from luminosity was the black collar round the throat; and while the inferior surface of the pectoral, anal, and caudal fins shone with splendor, their superior surface (including the upper lobe of the tail fin) was in darkness, as were also the dorsal fins and the back and summit of the head.