THE SALMOX FAMILY. 333 



fishing is useless ; but such a water when it is clearing, or 

 a fall water that is not discoloured, is highly favourahle. 



ITie two golden maxims for fly-fishing are, first, to keep 

 as far from the bank and as much out of sight as possible ; 

 and secondly, always to use finer tackle than any one else 

 on the river, — and (your skill being equal) you will always 

 catch the most fish. As it has been cleverly parodied, 

 " Tell me what your tackle is, and I will tell you what 

 your basket is." 



Principal Characteristics of the Common Trond (Salmo fario). (Taken 

 from a Hampshire fish, 12 inches in length.) — Length of head com- 

 pared to length of head and body, without taU-fin, as 1 to 4 : depth 

 of body rather greater than length of head. Profile of back and belly 

 about equally convex. Head blunt; lower jaw longest when the 

 mouth i5 open, but shutting within the upper jaw on its beinpr closed. 

 Back-fin commencing halfway between point of nose and commence- 

 ment of upper rays of tail-fin ; third ray of back-fin longest, and longer 

 than base of fin. Small back-fin commencing halfway between origin 

 of large back-fin and upptr extremity of tail-fin ; pectoral fin two- 

 thirds of length of head ; ventral fins tmder middle of first back-fin, and 

 halfway between origin of pectoral fin and end of base of anal fin ; 

 anal fin beginning halfway between origin of ventral fin and com- 

 mencement of lower rays of taH-fin. Tail slightly forked, veri- gra- 

 dually becoming square, or slightly convex in very old fish (as shown 

 in figiu'e, p. 320). Form of gUl-cover, see figure at p. 30. Pyloric 

 caeca * seldom exceeding 46 in number. Teeth numerous, strong, and 

 curving inwards, in six rows on upper surface of mouth and jaw, and 

 four on lower. (See also p. 35; and for distinguishing features between 

 teeth of Common Trout and Sea-Trout, p. 309.) Teeth (as through- 

 out the Salmon and Trout family) larger in males than in females. 



* The pyloric caeca are narrow pouches or cidi-de-sac, more or less 

 numerous, attached to the pylorus or mouth of the intestines. 



