TION. 



Class IV. GRAYLING SALMON. 415 



swift swimmer, and disappears like the tran- 

 sient passage of a shadow, from whence we 

 believe is derived the name of Umbra. 



Effugiensque oculos celeri levis Umbra natatu.* 

 The Umbra swift escapes the quickest eye. 



Thymalus and Thymus, are names bestowed 

 on it on account of the imaginary scent, com- 

 pared by some to that of thyme ; but we never 

 could perceive any particular smell. 



It is a fish of an elegant form ; less deep than Descrif- 

 the trout; the largest we ever heard of was 

 taken near Ludlow, which was above half a yard 

 long, and weighed four pounds six ounces, but 

 this was a very rare instance. The irides are 

 silvery, tinged with yellow ; the teeth very mi- 

 nute, seated in the jaws and the roof of the 

 mouth, but none on the tongue; the head is 

 dusky ; the covers of the gills of a glossy green ; 

 the back and sides of a fine silvery grey, but 

 when the fish is just taken, varied slightly with 

 blue and gold ; the side-line is strait ; the scales 

 large, and the lower edges dusky, forming strait 

 rows from head to tail. The first dorsal fin 

 has twenty-one rays ; the three or four first are 

 the shortest, the others almost of equal lengths; 

 this fin is spotted, all the others are plain ; the 

 tail is much forked. 



* Ausonii Mosel. go. 



