A STUDY ON TROUT AND YOUNG SALMON. 267 



Sometimes these flukes are quite lightly parted from the 

 pigment of the hack, by small intervals of a little lighter 

 colour. Small marks or spots of a light bluegrey colour 

 may sometimes occur between the lower points of the flukes. 

 Between every one of these flukes, which faintly resemble marks 

 from fingers soiled with blue lead paint, is a bright red spot, 

 the colour of red sealing wax. This spot is as a rule situated 

 right in or by the lateral hue. Sometimes red spots may occur 

 higher up or lower down on the body; but, in this case, they 

 are not arranged in any regular order and their number is never 

 great, the highest number within my experience being 2 or 3. 



The dorsal fin has the colour of the back with a couple of 

 irregular rows of dark spots. 



The caudal fin is greyish blue, semitransparent with blackish 

 flukes. 



The adipose fin has the colour of the back. 



The anal and ventral fins are white. 



On the side turning towards the body the pectoral fins are 

 bluish-black. On the outer side they are whitish towards the 

 base, but gradually become more bluish-black towards the points 

 of the finrays. 



In the trout the back is more brownish-green-grey. 



This pigment of the back is not as in the case of the sal- 

 mon, continued scallop- or fluke-wise down the sides of the fish ; 

 it is always interrupted. In the trout large oval spots thus 

 correspond to the flukelike markings in the salmon. These spots 

 are always separated by relatively large intervals from the pig- 

 ment of the back. Between these spots are found smaller spots 

 dorsally as well as ventrally. None of these large side spots 

 are as distinct and sharply limited as in the salmon. Along the 

 lateral line runs a row of small red spots. As well above as 

 below this line, runs a similar line of small red spots arranged 

 just above and below the intervals between the spots along the 



