60 



ANGLING. 



SECTION V. 



The Muscular movements of Fishes. 



THE vertebral column, composed of numerous 

 articulations, united by cartilages which permit of 

 certain movements, curves with great facility from 

 side to side ; but the vertical motion is much more 

 restricted, chiefly in consequence of the projection 

 of the upper and under spiny processes of the ver- 

 tebrae. The great organ of movement in all fishes 

 is the tail. The muscles, by which it is brought 

 into play, extend in lengthened masses on either 

 side of the vertebral column. The body, being 

 supported chiefly by the swimming bladder (which, 

 however, is absent in several species), is propelled 

 forwards by the rapid flexure of the extremity 

 acting laterally upon the resistance offered by the 

 water. Generally speaking, neither the pectoral 

 nor the ventral fins are of any material use during 

 swift progressive motion ; they rather serve to 

 balance the body, or to aid its gentler movements 

 while in a state of comparative repose. In flying 

 fishes, as they are called, the pectoral fins are of 

 such great length and expansion as to support these 

 creatures in the air ; and the strength of muscular 

 action might probably suffice even for a longer flight, 

 but for the necessity of constant moisture for the 

 purposes of respiration. The drying of the gills 

 in an individual of this class is attended by results 

 analogous to those produced by submersion in the 



