GENERIC CHARACTER OF THE TROUT. 15 



those fish which have soft-rayed fins, with their 

 ventral fins placed far behind and unattached to 

 the bone of the shoulder. All the SALMONID^E 

 have eight fins, namely, two pectoral or breast 

 fins; two ventral fins, on the belly next below 

 the pectorals ; the anal fin, behind the ventral 

 fins ; the caudal or tail fin ; and two dorsal or 

 back fins, the hindermost small, fleshy, and 

 without rays. 



Although the trout in different localities vary 

 considerably both in appearance and quality, it is 

 by no means a solitary opinion that there exists 

 but one species ; the difference of form, size, and 

 colour in the trout of different localities being 

 accounted for by the operation of their food and 

 of the water they inhabit. Some naturalists, 

 however, think and among them is Mr. Yarrell 

 that more than one species, and that several 

 varieties, of the common trout, exist in this coun- 

 try ; and supposing those gentlemen to classify 

 the lake trout and the gillaroo trout of Ireland * 

 in this latter category, they are, perhaps, suffi- 



* A remarkable peculiarity of the gillaroo trout is the 

 construction of its stomach, which has been likened to the 

 gizzard of a bird, and accounted for from the circum- 

 stance of the principal food of this fish being shell-fish, 

 for the constant assimilation of which its stomach has thus 

 become permanently adapted. 



