THE SALMON 195 
tissue, an outgrowth of the general envelope of the body which 
underlies the epiderm or outer skin. Of the purpose of this 
peculiar excrescence it boots not to treat, though there be 
many who have done so. Various functions have been 
assigned to it on purely speculative grounds. Some would 
have it to be a weapon of offence ; but it seems to be the 
very reverse of this, diminishing the destructive power of the 
jaws by partially closing the mouth. All we really know 
about it is that it appears on the males periodically at the 
breeding season, and is re-absorbed when the reproductive 
function is finished and the fish becomes a kelt. In old 
males, this knob is never completely absorbed, and the 
head becomes permanently elongated in comparison with that 
of the female. But it is to be noted that occasionally 
females develop the knob also, though not to such an 
extent as the males. 
One use often, but erroneously, ascribed to the knob or 
hook, is that of preparing a nest or bed for the spawn ; and 
Process of 1t Shows how difficult it is to stamp out an error 
spawning. which has once received currency that people may 
still be heard repeating this silly fable. So long ago as 1656, 
Richard Franck, as observant in zoology as he was bitter 
in theology, accurately described the process of spawning 
as he himself had watched it. The female swims upon a 
gravelly shallow, where the current is brisk, but not violent ; 
and, having chosen a spot to her fancy, rolls upon her side and 
flaps her tail rapidly so as to fan up the gravel, thereby ex- 
cavating for herself a hollow. This trough is usually called a 
‘“‘redd ”* in the north, and when the fish have not been delayed 
by want of floods from ascending the river, several days may 
be occupied in making it ; but when salmon have been retarded 
by drought in arriving at the spawning-ground, the redd is 
excavated in more summary fashion. So soon as it is finished 
* Je.,a place made “ready” or prepared. ‘‘ Redd me a place” in 
Lowland Scots means “ Prepare room for me.” 
