22 THE NATURALIST. 



influence. Many an assailant must be most unexpectedly stopped by it ; and the fishes 

 which are endowed with it being, in general, of slow motion, lurk until their victims 

 approach within the influence of their deadly and peculiar power. 



The reproduction and migration of fish is another part of their history full of interest. 

 They are, with a few exceptions, oviparous, and fruitful to a most surprising degree 

 so much so, that if the whole ova were to be matured, bounds could not be assigned to 

 them, and the expanse of the waters would be crammed j but among the millions of 

 ova which are deposited, those hatched to maturity will not exceed one in the thousand, 

 perhaps a much less proportion, and in their great fertility we see both a beneficent 

 design in furnishing an ample supply of food for many of the inhabitants of the same 

 element, and for the numerous tribes of waterfowl which, at some seasons, feed entirely 

 on the eggs and fry 5 while, on the other hand, without this abundant power of gene- 

 ration, a stock could not be saved from the numerous enemies of sea and air to which 

 they are nearly cxnstantly exposed. In general, the eggs are deposited in water com- 

 paratively shallow, upon rocks, or gravelly or sandy banks, on aquatic plants, or marine 

 algse, or in holes formed in the banks or borders of the lakes or rivers ; and to the 

 strong instinctive principle which impels these creatures to seek suitable situations for 

 the deposition of their spawn, do we owe the abundant supply of fish which annually 

 resort to our shore. 



There is one circumstance in the breeding of fishes which requires notice that of no 

 care being bestowed on the ova, or young, after a place has been selected and finished 

 for the deposition, or after they are hatched. There seem, however, here also, to be 

 exceptions. The Caltichthys littoralis makes a regular nest of long leaves, or grass, in 

 which they lay their eggs in a flattened cluster, and cover them over most carefully. 

 They remain by the side of the nest till the spawn is hatched, with as much solicitude 

 as a hen guards her eggs, both male and female, for they are monogamous, steadily 

 watching the spawn, and courageously attacking any assailant. 



In their economical uses to man, fish are principally important as an article of food, 

 and from the employment they afford to the more dependent classes j but oil is the com- 

 modity greatest in value and quality, produced from them. The quantity of fish killed 

 for these purposes, is truly immense. What then will be the aggregate of the creatures 

 in this department of zoology which are yearly consumed in our commerce ? Isinglass 

 is made from the swimming bladders ; glue from the coarser refuse of fins ; artificial 

 pearls from the scales, &c. 



GENUS PERCA. 



PERCH. 



The genus Perca, first and typical of the family, is familiarly known in the form of 

 the Common Perch. The characters may be shortly stated: Preopercle, toothed; 

 opercle, spined ; suborbitary bones, delicately toothed ; tongue free. The dorsal fins 

 are very powerful, the spines strong and sharp. The scaling moderately large, and with 

 the posterior edge toothed. Swimming bladder very large. Number of vertebrae in the 

 common species, forty-two. They are all inhabitants of the fresh waters, delighting in 

 lakes and still running streams. Feed on marine insects and small fish. The colors are 



