[mcmuRRIcH] LIFE CYCLES OF THE PACIFIC COAST SALMON 23 
the length and breadth of the ossicles from three fish measuring respect - 
ively 64.0, 74.0 and 74.0 em., being 5 mm. by 3.5 mm., 5.5 mm. by 3.0 
mm., and 5.25 mm. by 3.0 mm. 
The markings on the ossicles of the 74.0 em. fish whose scales 
showed the broken band that I have identified as a spawning mark, 
did not differ from those shown by other fish in any particulars that 
might be correlated with the supposed exceptional life history. 
THE Cono (O. kisutch) (WALBAUM). 
The three species so far considered agree in the essential features 
of their history, the cycle being one of four years. In the two remaining 
species the conditions are quite different, the life cycle being one of 
only two years, the fish becoming adult at a time when those of the 
other three species have merely reached the grilse stage. At least this 
is the story told by the scales and otoliths, but it is told with such 
distinctness that it seems unquestionable. 
I obtained for examination six Coho, whose lengths were respect- 
ively 67.5 em., 64.5 em., 64.0 em., 63.5 cm., 60.5 em. and 44.0 em. 
THE SCALES. 
In all six individuals, notwithstanding the small size of one of 
them, the arrangement of the scale markings was essentially the same, 
(Plate X. fig. 1). Around the central nucleus was a zone of narrow 
lines, representing, as in other cases, the growth in fresh water; then 
follows a zone of broad lines, representing the growth of the first 
summer in the sea, and this is followed by a zone of narrow lines, 
representing the winter “check.” Finally the periphery of the scale is 
formed by a zone of broad lines, representing the second summer in the 
sea. There is then but one zone representing the winter “check,” 
instead of three as in the species already described, and the inference 
is that this species returns to the spawning ground as an adult fish 
in its second year. 
In connection with this difference in the life cycle may be mentioned 
a difference in the habitsof the Coho,namely,it apparently feeds actively 
during its return to fresh water, since it is readily captured by trolling, 
and I have taken small crustacea from the mouth of fish captured in 
this manner. Further it is one of the forms that are to be seen leaping 
vigorously from the water during the period of the run. In these 
respects it differs markedly from the adult Sockeye, which cannot be 
prevailed upon to take the hook, be it prepared never so appetizingly 
and presented in the most tempting manner. The Spring Salmon, are 
