20 THE ROYAL SOCIETY OF CANADA 
ment of the scale markings. One of these is the abundance or paucity 
of food material, which is shown by the greater or lesser breadth of the 
annual zones, while the “check” and winter bands are to be ascribed 
to the second factor, which is probably temperature. It seems probable 
that the two fish under consideration have wandered during the summer 
into a cold zone, perhaps into water deeper than usual, so suffering 
a “check,” and have later returned to a warmer zone, the growth 
lines on the scales thereupon returning to the usual summer arrange- 
ment. 
As in the case of the Sockeye none of the Spring Salmon examined 
show any indications of a spawning scar upon their scales. The life- 
cycle is essentially the same in both species; it is one of four years 
and reproduction takes place at the close of the fourth year and then 
only, except, of course, in the case of grilse. 
THE OTOLITHS. 
The sagitta of the Spring Salmon (Text-fig. 5) is very similar to 
that of the Sockeye in its general form, the most evident difference 


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Text-fig. 5.—Left Sagitta of a Spring Salmon, 91 .5 cm., in length seen from the 
lateral surface. The outlines of the groove for the nerve have 
been drawn in, as if the ossicle were transparent. 
being that the groove for the nerve on the medial surface is much 
more uniform in width and is not obliterated in the middle of its length 
in any of the ossicles examined. The groove is also decidedly nearer 
the upper border of the ossicle than in the Sockeye. In size, however, 
there is a marked difference in favour of the ossicles of the Spring 
Salmon. Thus while in a Sockeye 65.5 cm. in length the greatest length 
and breadth of the sagitta were respectively 5.0 mm. and 3.25 mm., 
the corresponding measurements of an ossicle from a Spring Salmon 
