SWIFTNESS OF FISHES. 187 



If the whole economy of the world of fishes were opened to 

 our view, the magnificent picture would, no doubt, give us ad 1 - 

 ditional reasons for admiring the infinite wisdom of the Creator ; 

 but the little we do know suffices to convince us that the 

 same wonderful harmony existing between the anatomical 

 structure and the outward relations or mode of life in birds and 

 mammiferous quadrupeds is also to be found in fishes, and that 

 these creatures, though occupying a lower grade in Creation, are 

 no less beautifully adapted to the peculiar element in which 

 they are destined to live and. move. 



This strikes us at once in their external form, which, though 

 subject to great variety, being sometimes spherical as in the 

 globe-fish, or cubical as in the ostracion, or expanded as in the 

 skate, or snake-like as in the eel, is generally that of an elon- 

 gated oval, slightly compressed laterally, a shape which enables 

 the fishes to traverse their native fluid with the greatest celerity 

 and ease. We wisely endeavour to imitate this peculiar form 

 in the construction of our ships, yet the rapidity with which the 

 fastest clipper cleaves the waters is nothing to the velocity of an 

 animal formed to reside in that element. The flight of an 

 arrow is not more rapid than the darting of a tunny, a salmon, 

 or a gilt-head through the water. It has been calculated that a 

 salmon will glide over 86,400 feet in an hour, that it will 

 advance more than a degree of the meridian of the earth in a 

 day, and that it could easily make the tour of the world in some 

 weeks, were it desirous of emulating the fame of a Cook or of 

 a Magellan. Every part of the body seems exerted in this 

 despatch ; the fins, the tail, and the motion of the whole back- 

 bone assist progression ; and it is to this admirable flexibility of 

 body, which mocks the efforts of art, that fishes owe the 

 astonishing rapidity of their movements. 



Whales and dolphins move onwards by striking the water 

 in a vertical direction, while fishes glide along by laterally 

 curving and extending the spine. In some species, such as the 

 eel, the whole body is flexible ; but most of them paddle away 

 with their tail to the right and left, and are thus driven forwards 

 by the resistance of the water. Consequently the power of 

 fishes is chiefly concentrated in the muscles bending the spine 

 sideways, and generally we find these parts so much developed 

 as to form the greatest part of the body. 



