I02 



THE SEA-TROUT 



spots on the skin of the sea-trout parr are repeated on the silvery 

 surface of the sea-trout smoh as if they were endeavouring to shine 

 through, but they are not now so conspicuous because they have already 

 begun to be broken up into the X-shape which so often characterises 

 the spots of the mature fish. 



In supplement of the foregoing notes upon the various distinctions 

 which characterise the young of salmon, sea-trout and trout, I may add 

 a table of the distinctions which have been noted by a Norwegian 

 observer, Mr. Hartig Hiiitfeldt-Kaas, as occurring between the parr 

 and smolts of salmon and trout, i.e., sea-trout. The following rough 

 translation has been kindly made for me by Mr. Hutton : — 



Salmon. 

 The body is comparatively more 

 delicately and more pointedly shaped 

 with a long and slender tail. 



The head is set lower on the body 

 and more finely shaped. At the first 

 glance the head seems to be exception- 

 ally long, but this is due to the fact 

 that the front portion (viz., the nose 

 and mouth) is distinctly shorter than 

 the trout's, so that the gill-covers are 

 longer in proportion. 



The eye is comparatively large and 

 is placed well forward in the head. A 

 perpendicular line drawn downwards 

 from the posterior margin of the pupil 

 will as a rule not touch the posterior 

 end of the maxillary bone. 



The mouth is comparatively small, 

 and the lengtli (measured to the 

 posterior edge of the maxillary bone) 

 is equal to about if diameters of the 

 eye. 



All the fins (with the exception of 

 the adipose fin) are longer than the 

 trout's. 



The tail fin is distinctly V-.shaped, 

 and the extremities of each lobe 

 are either pointed or very slightly 

 rounded. 



Trout. 



The body is comparatively clumsy 



with a short thick tail. 



The head is comparatively larger 

 and more clumsily shaped than the 

 parr's. The front part is much 

 longer, and the nose is longer and 

 deeper, and the lower jaw heavier. 

 Consequently the mouth is larger, 

 and therefore the maxillary bone is 

 distinctly longer than the parr's. 



The eye is distinctly smaller. 

 Although it is set further back in the 

 head, a perpendicular line drawn 

 downwards from the posterior edge of 

 the pupil will either cut or touch the 

 maxillary bone. 



The mouth is large, and the length 

 (measured to the posterior edge of the 

 maxillary bone) is about 2| to 3 times 

 the diameter of the eye. 



All the fins (with the exception of 

 the adipose fin) are shorter than the 

 parr's. 



The back of the tail fin when 

 stretched out forms either a straight 

 line or is only slightlv concave, and 

 ihe lobes are broader and more 

 rounded. 



