OSSEOUS FISBES. 531 



mandibles of the beak of the parrot. They are perfectly arranged to 

 crush the shells of the molluscs, as well as the resisting envelope of 

 the crustaceans on which they feed. The skin of these fishes bristles 

 with small slightly-projecting spines, the number of which compensate 

 for their brevity, which repel their enemies, and even wound the hand 

 that would grasp them. They enjoy, besides, a singular faculty ; they 

 can inflate the lower part of their body, and give it an extension so 

 considerable that it becomes like an inflated ball, in which the real 

 shape of the animal is lost. This result is obtained by the introduction 

 of an immense quantity of air into the stomach when it wishes to 

 ascend to the surface. The species of globe-fish are numerous. Some 

 of them are common in the Nile, where they are frequently left ashore 

 during the annual inundations. 



The Globe-fish (Orthagoriscus mola), in the upper part of the en- 

 graving, is easily distinguished from the Tetrodons by its compressed 

 spineless body ; being very round in its vertical contour, it has been 

 compared to a disk, and more poetically to the moon whence its 

 popular names to the great circular surface of which the dazzling 

 silvery white disk bears some resemblance. But it is especially during 

 the night that it justifies the name given to it. Then it shines brightly, 

 from it own phosphorescent light, at a little distance beneath the sur- 

 face. On very dark nights the globe-fish is sometimes seen swimming 

 in the soft light which emanates from its bodj^, the rays rendered 

 undulating by the rippling of the water which it traverses, so as to 

 resemble the trembling light of the moon half-veiled in misty vapours. 

 When many of these fishes rove about together, mingling their silvery 

 trains, the scene suggests the idea of dancing stars. The moon-fish 

 is common in the Mediterranean, and sometimes reaches the markets 

 of Paris. It is about thirty inches in length, and its weight is con- 

 siderable. Its flesh is fat and viscous, and by no means pleasant 

 to eat. 



The Diodons (Fig. 358) only differ from the globe-fish in the form 

 of their bony jaws, each forming only one piece. They seem to have 

 two teeth, whence their name, from /?, two, obovs, teeth. They differ 

 also in their spines, which are much larger than those of the globe-fish. 

 These fishes may be said to be the hedgehogs and porcupines of the 

 sea. Like the globe-fish, they can erect their spines and inflate their 

 bodies. 



2 M 2 



