62 THE SEA-TROUT 



between the sea-trout proper and the alleged " bull trout." I have 

 already considered the matter at some length in my introductory chapter 

 and there is the less occasion to labour the subject here. Two points, 

 however, may be referred to. 



We have seen that Mr. Regan agreed that a slight difference might 

 sometimes be recognisable between western and eastern sea-trout. In 

 his own words, " the Sewen (5. caiiibricus) of Wales, Ireland, and our 

 Western coasts often differ from the Sea-trout (5. albzis) of the east 

 coast, in having a longer head, a larger mouth with stronger jaws, the 

 suboperculum projecting backwards beyond the operculum, and the fins 

 somewhat larger, the lobes of the caudal especially being more pro- 

 duced." Now it was partially in respect of the shape of the gill-covers 

 that Yarrell distinguished between the " orev trout " of the Tweed, and 

 other rivers, notably tho.se of South Wales, " where it is called the 

 Sewin," and other sea-trout. He found that " The operculum is 

 larger; the free vertical margin much more straight; the inferior 

 posterior angle more elongated backwards; the line of union with the 

 suboperculum not so oblique, but nearly parallel with the axis of the 

 body of the fish; the inferior edge of the suboperculum parallel to the 

 line of union with the operculum; the interoperculum much deeper 

 vertically; the vertical edge of the preopcrculum more sinuous." The 

 reader who admires the zealous exactness of this description may trace 

 its various parts with reference to the diagram (Fig. 15) given at page 

 56. I shall merely note that Mr. Regan's observation of " the 

 suboperculum projecting backwards beyond the operculum " and 

 Yarrell's of the operculum having its " inferior posterior angle more 

 elongated backwards " both help to describe the fact that nearly always 

 the gill-covers of sea-trout, unlike those of salmon, project backwards 

 in a curve considerably more abrupt than the circumference of a true 

 circle, the free edge of the suboperculum almost invariably projecting 

 beyond the edge of the operculum. That there is any distinction in 



