=The Salangidæ, or Icefishes.=—Still more feeble and insignificant are the species of _Salangidæ_, icefishes, or Chinese whitebait, which may be described as _Salmonidæ_ reduced to the lowest terms. The body is long and slender, perfectly translucent, almost naked, and with the skeleton scarcely ossified. The fins are like those of the salmon, the head is depressed, the jaws long and broad, somewhat like the bill of a duck, and within there are a few disproportionately strong canine teeth, those of the lower jaw somewhat piercing the upper. The alimentary canal is straight for its whole length, without pyloric cæca. These little fishes, two to five inches long, live in the sea in enormous numbers and ascend the rivers of eastern Asia for the purpose of spawning. It is thought by some that they are annual fishes, all dying in the fall after reproduction, the species living through the winter only within its eggs. But this is only suspected, not proved, and the species will repay the careful study which some of the excellent naturalists of Japan are sure before long to give to it. The species of _Salanx_ are known as whitebait, in Japan as _Shiro-uwo_, which means exactly the same thing. They are also sometimes called icefish (_Hingio_), which, being used for no other fish, may be adopted as a group name for _Salanx_. The species are _Salanx chinensis_ from Canton, _Salanx hyalo cranius_ from Korea and northern China, _Salanx microdon_ from northern Japan, and _Salanx ariakensis_ from the southern island of Kiusiu. The Japanese fishes are species still smaller and feebler than their relatives from the mainland. =The Haplochitonidæ.=—The _Haplochitonidæ_ are trout-like fishes of the south temperate zone, differing from the _Salmonidæ_ mainly in the extension of the premaxillary until, as in the perch-like fishes, it forms the outer border of the upper jaw. The adipose fin is present as in all the salmon and smelt. _Haplochiton_ of Tierra del Fuego and the Falkland Islands is naked, while in _Prototroctes_ of Australia and New Zealand the body, as in all salmon, trout, and smelt, is covered with scales. _Prototroctes maræna_ is the yarra herring of Australia. The closely related family of _Galaxiidæ_, also Australian, but lacking the adipose fin, is mentioned in a later chapter. [Illustration: FIG. 86.—Icefish, _Salanx hyalocranius_ Abbott. Family _Salangidæ_. Tientsin, China. ] =Stomiatidæ.=—The _Stomiatidæ_, with elongate bodies, have the mouth enormous, with fang-like teeth, usually barbed. Of the several species _Stomias ferox_ is best known. According to Dr. Boulenger, these fishes are true _Isospondyli_. [Illustration: FIG. 87.—_Stomias ferox_ Reinhardt. Banquereau. ] _Astronesthidæ_ is another small group of small fishes naked and black, with long canines, found in the deep sea. The _Malacosteidæ_ is a related group with extremely distensible mouth, the species capable of swallowing fishes much larger than themselves.