554 ICHTHYOLOGY. 



lipped Grey Mullet, (Mugil Chelo,) to be 13,000,000; in the 

 Cod-fish, (Gadus Morrhua^ 11,000,000; in the Turbot, (Pleu- 

 ronectes maximus,) 9,000,000 ; in the Plaice, (P. platessa,) 

 6,000,000; in the Carp, (Cyprinus carpio,) 600,000 to 700,000; 

 in the Perch, (Perca fluviatilis, ) 71,000. 



It has been estimated that the progeny of a single Herring, if 

 allowed to multiply, undisturbed for thirty years, would not only 

 be sufficient to meet every demand for this fish, but become even 

 inconveniently numerous; and that, too, notwithstanding hardly 

 one among the millions of young Herrings comes to maturity, in 

 consequence of the ravages made by rapacious fish, and by other 

 means. Although so extensively used, the supply of this fish is 

 always found equal to the demand. The same might be said of 

 the Cod, the Mackerel, the Tench, &c. 



The longevity of fishes seems to be undoubted, however it be 

 true that few reach their natural term of years. Pike and Carp 

 kept in fish ponds, have been known to live to a great age. A 

 Pike taken in Prussia, in 1754, bore a ring which testified to its 

 having been placed in the pond two hundred and sixty-seven 

 years before ; how old it was when put in was unknown. Carp, 

 it is clearly shown, have attained the age of a century. Buffon 

 speaks of one that was one hundred and fifty years old. 



"Cartilaginous fishes," says Swainson, "continue to grow all 

 their lives ; and as many of these, particularly the Rays, habitu- 

 ally live in the deep recesses of the ocean, and thus seldom run 

 the risk of being captured by man, we may probably attribute 

 their enormous and almost incredible size to their great age." 

 It is thought to be "a rare thing for a fish to die of natural de- 

 cay." But owing to the ravages made among them, the actual 

 average of life is with fishes of comparatively short duration. 

 They are capable of enduring great extremes of temperature, 

 a fact which may be regarded as indicating their low place in 

 the scale of organization. Experiments have shown that several 

 species of fresh-water fish can live many days in water so hot 

 that the hand could not be held in it a single minute. Eels have 

 been alive in hot springs, in which the temperature is pretty 

 regularly 113o Fahr. But such cases are far less wonderful 

 than that recorded by Humboldt and Bonpland, who "saw living 

 fishes, apparently in health and vigor, thrown up from the bottom 

 of a volcano, with water and hot vapor that raised the thermom- 

 eter to 210o Fahr., a heat only two degrees less than that of 

 boiling water] " 



On the other hand, the cold of freezing does not always destroy 

 the life of fishes. Eels and Perch are conveyed from place to 



