Fig. 112.—Albula vulpes (Linnæus). Transformation of the Ladyfish, from the translucent, loosely compacted larva to the smaller, firm-bodied young. Gulf of California. (After Gilbert.)
Fig. 113.—Development of the Horsehead-fish, Selene vomer (Linnæus). Family Carangidæ. (After Lütken.)
Some fresh-water fishes are very fragile, dying soon in the air, often with injured air-bladder or blood-vessels. They will die even sooner in foul water. Other fishes are extremely tenacious of life. The mud-minnow (Umbra) is sometimes ploughed up in the half-dried mud of Wisconsin prairies. The related Alaskan blackfish (Dallia) has been fed frozen to dogs, escaping alive from their stomachs after being thawed out. Many of the catfishes (Siluridæ) will live after lying half-dried in the dust for hours. The Dipnoan, Lepidosiren, lives in a ball of half-dried mud during the arid season, and certain fishes, mostly Asiatic, belonging to the group Labyrinthici, with accessory breathing organ can long maintain themselves out of water. Among these is the China-fish (Ophiocephalus), often kept alive in the Chinese settlements in California and Hawaii. Some fishes can readily endure prolonged hunger, while others succumb as readily as a bird or a mammal.
Fig. 114.—Ice-fish, Salanx hyalocranius Abbott. Family Salangidæ. Tientsin, China.
