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THE ROYAL SOCIETY OF CANADA 
It seems probable that grilse Dog Salmon may also occur, although 
I am unable to make a definite statement on that point based on direct 
personal observation. In one of the 74 cm. fish, however, an interesting 
arrangement of the scale markings occurs, which I interpret as indicat- 
ing the occurrence of grilse forms. The fish was apparently a four 
year old form, but the “check” zones representing the first and second 
winters spent in the sea are very close together (Plate IX.), being 
separated only by a very narrow band in which the lines are very much 
broken and irregular. Indeed, so close are the two “check” zones 
that at first I regarded them as a single zone, whose formation had, 
for some unknown reason, been interrupted, the fish having been, 
accordingly, three years old when captured. This, however, was such 
an extraordinary variation that it seemed preferable, on further examin- 
ation, to interpret the band of broken lines as representing the second 
summer spent in the sea, and the question then arose as to the mean- 
ing of its unusual appearance. It has been determined by the observa- 
tions of Hutton and others that in the Atlantic Salmon the spawning 
period is clearly marked upon the scales by a scar, closely resembling 
in its appearance the band of broken lines under consideration, and 
I am inclined to regard the band as a spawning mark. If this be its 
correct interpretation, then the fish was a four year old form, but 
during its second summer, it returned to fresh water as a grilse and 
spawned, and after spawning it again returned to the sea for two 
additional years. When captured it was, accordingly, for the second 
time on its way to the spawning grounds in its fourth summer. 
The probabilities for such a life history are much greater in the 
case of the Dog Salmon than in either the Sockeye or the Spring Salmon, 
since the first named finds its spawning grounds at no very great dist- 
ance from the sea, whereas the Sockeye and Spring seek rather the head 
waters of the larger rivers. The chances of a return to the sea after 
spawning are much greater therefore for the Dog Salmon, and although 
it is well known that even in this species the majority of the adult fish 
die on the spawning grounds, yet the possibility of a grilse surviving 
the spawning season and returning to the sea is far from being excluded. 
It will be interesting to determine, by observations on a much larger 
number of fish, whether this is of frequent occurrence in the case of the 
Dog Salmon. 
THE OTOLITHS. 
In their form and markings the sagittæ of the Dog Salmon resemble 
so closely those of the Sockeye that a detailed description of them seems 
unnecessary. In size they also correspond with those of the Sockeye, 
