24 THE ROYAL SOCIETY OF CANADA 
it is true, taken by trolling, but so far as Iam aware Sockeye never are. 
How it is with the Dog Salmon I do not know. 
THE OTOLITHS. 
The sagittæ of the Coho closely resemble those of the Sockeye in 
form, the most striking difference being a decided outward bend of the 
portion of the ossicle lying between the rostrum and antirostrum and 
forming the floor of the acustic sulcus; as a consequence the ossicles 
are not flat as in the Sockeye. In size also they closely resemble those 
of the adult Sockeye, their greatest length averaging about 5.25 mm., 
and their breadth about 3.0 mm. In the 44.0 cm. fish these measure- 
ments were somewhat smaller, the length being 4.75 mm. and the 
breadth 2.5 mm. 
The growth markings, however, were very indistinct and yielded 
very little information as to the life history of the fish. The central 
nucleus was always quite distinct, as was also the zone representing the 
life in fresh water, but throughout the remainder of the ossicle there 
was not the distinct separation of dark and clear zones shown by the 
other species. The material added during the period spent in the sea 
was very largely of the quality giving the clear appearance, the darker 
more organic material being massed towards the posterior portion of 
the ossicles. From this dark area a narrow line extended forward to a 
greater or less distance in such a position as to indicate that it had 
been formed during the first summer, but a corresponding dark line for 
the second summer was either absent or so feebly developed as to be 
uncertain. | 
THe HuMPBACK, O. gorbuscha (WALBAUM). 
Of this species I had six individuals for examination, averaging 
58.5 em., in length and varying from 54.0 cm., to 63.5 cm. 
THE SCALES. 
One of the distinguishing peculiarities of the Humpback is the 
small size of its scales. They show, however, the same arrangement of 
the markings as the Coho, so that the inference to be derived from their 
study is that the species has a life cycle of two years. It also shows 
in common with the Coho the habit of leaping vigorously from the water 
while on its return to the spawning grounds, but I cannot state whether 
it is also taken with the trolling hook. 
