FORM AND LOCOMOTION 



25 



Turning to the second of the primary methods of locomotion, 

 it may be noted that movements essentially the same as those 

 of the body may be localised in one or more of the fins, and the 



Fig. 10. — FIN MOVEMENTS USED BY FISHES IN SWIMMING. 



A. Bow-fin {Amia calvd),X^^; b. Electric Eel (Electrophorus electncus),Xi ; 

 c. File-fish {Monacanthus sp.), X J ; d. Ray (Raia sp.), X i. (After Breder.) 



same kind of series occurs, ranging from a serpentine, un- 

 dulating motion like that of the Eel to a fan-like waggle which 

 recalls the tail movements of the Trunk-fish. It has been 



