68 SALMONIA. 



that it is produced by the sea trout and 

 common trout. In a small river which runs 

 into the May, near Ballina in Ireland, I 

 once caught in October a great number of 

 small sea trout, which were generally of 

 half a pound in weight, and which were all 

 males; and unless it be supposed that the 

 females were in the river likewise, and would 

 not take the fly, these fish, in which the 

 spermatic system was fully developed, could 

 only have impregnated the ova of the com- 

 mon river trout. The sea trout and river 

 trout are, indeed, so like each other in 

 character, that such a mixture seems ex- 

 ceedingly probable; but I know no reason 

 why such mules should always continue small, 

 except that it may be a mark of imperfec- 

 tion. The only difference between the par 

 and common small trout, is in the colours, 

 and in its possessing one or two spines more 

 in the pectoral fin. The par has large blue 

 or olive bluish marks on the sides, as if they 

 had been made by the impression of the 

 fingers of a hand ; and hence the fish is 

 called in some places fingerling. The river 



