6 SALMONID^E. 



bone, with a few only on the vomer between the palatine 

 bones : the teeth on the vomer seldom exceeding two in 

 number, sometimes only one, and that placed at the most 

 anterior part ; no other teeth extending along the vomer as 

 in the Salmon-Trout, and more particularly so in some 

 of those Trout that do not migrate. 



The inner surface of the pectoral fin is in part dusky : 

 the tail very much forked when young ; the central caudal 

 rays growing up, the tail is much less forked the second 

 year, and by the fourth year it is become nearly or quite 

 square at the end. 



The descriptions of the gill-covers of the other species 

 will be given in the account of the fish to which they 

 belong ; but it may be remarked here, that looking at 

 the form of the three gill-covers, it will be obvious that a line 

 drawn from the front teeth of the upper jaw to the longest 

 backward projecting portion of the gill-cover, in either spe- 

 cies, will occupy a different situation in respect to the 

 eye ; that the line will fall nearest the centre of the eye 

 in the first, that of the Salmon, and farthest below it in the 

 second, that of the Bull-Trout. 



As further specific distinctions in the Salmon, I may 

 add that, according to Dr. Richardson, the csecal appen- 

 dages are in number from sixty-three to sixty-eight; and 

 several observers have stated the number of vertebrae to be 

 sixty, which I have repeatedly found to be correct. 



Commencing, then, with the true Salmon, which ascend 

 the rivers, in the state as to colour before mentioned, sooner 

 or later in the spring or summer months, it is observed 

 that some rivers are much earlier than others, the fish 

 in them coming into breeding condition and beginning 

 to spawn at an earlier period. 



Rivers issuing from large lakes afford early Salmon, the 



