THE TALE OF THE FISHES 



in a period immediately preceding the Pleistocene. 

 Professor Bashford Dean of Columbia University, 

 following Zittel, carries the origin back into the Cre- 

 taceous Age. Professor Newbury figured the fish in Plate 

 No. 1 which antedates Cretaceous forms by two geo- 

 logical ages (Triassic and Jurassic), but appears this 

 side of the devonian or "Age of Fishes." The broad 

 gibbous or convex tail suggests fitness to battle with 

 mill-race currents. That's what a truncate tail is for; 

 and it is conceivable that tails, the main organs of 

 propulsion, should square where whirlpool rapids are 

 to be stemmed and the mechanical needs of the swim- 

 mer become imperative. The wide paddle blades of 

 the salmon provoked the comment of Ausonius in his 

 Mosella : 



"Latae cujus vaga verbera caudae 



Gurgite de medio summas referuntur in undas" 



The whisking strokes of his broad tail bear him 

 up from the bottom of the raging stream quick to the 

 surface. 



In Neozoic time, quite near to man, although many 

 thousand years from us, trout and salmon and smelt 



39 



