NATURAL HISTORY OF THE QUINNAT SALMON. 
131 
derance of the grilse over the adult males and females is due to their being too small 
to be taken by the nets of lawful mesh. 
The cause or causes that lead to the production of the grilse form are not known. 
Mention is made in another jilace in this report of the sexual maturing of the male 
parrs that remain in fresh water during their first summer. It it possible that this 
stunts them and causes the production of grilse. If grilse were simply young indi- 
viduals that followed the adults into fresh water, we would expect to find females 
among them. The two forms can not be distinguished except in breeding fishes. 
The dwarfed form of the female is practically unknown. Among many thousand 
specimens handled at Battle Creek fishery only one dwarfed specimen was found. 
This was 1G inches in total length and weighed 2 pounds. Its ova were mature. 
Two spent male salmon, adult and grilse forms, Sfound dead on the rack at Battle Creek fishery October 28, 1900. 
Length from hinder edg'e of eye to base of tail, larger specimen 500 mm., smaller 455 mm.; weight, larger speci- 
men, 3,100 grams, smaller 1,200 grams. 
Comparative statemen t of ■ weight and length of the. snout in adult and grilse salmon of the same 
body length. 
Length from 
hinder edge 
of eye to base 
of caudal fin 
(centi- 
meters) . 
Weight in grams. 
Length of snout 
from hinder 
edge of eye 
(millimeters). 
Length from 
hinder edge 
of eye to base 
of caudal fin 
(centi- 
meters). 
Weight, in grams. 
Length of snout 
from hinder 
edge of eye 
(millimeters). 
Adult. 
Grilse. 
Excess 
of adult. 
Adult. 
Grilse. 
Adult. 
Grilse. 
Excess 
of adult. 
Adult. 
Grilse. 
40 
1,125 
1,025 
100 
68 
49 
2, 475 
2,375 
UK) 
77 
70 
41 
1,650 
1,000 
650 
75 
57 
49 
2,700 
1,425 
1,275 
79 
67 
43 
1,725 
1,575 
150 
66 
66 
50 
2,975 
1,725 
1 225 
92 
71 
43 
2,500 
1.600 
900 
66 
65 
51 
2, 775 
1,875 
900 
99 
75 
45 
2,350 
1,075 
1,275 
72 
65 
54 
3,700 
2, 425 
1,275 
90 
71 
40... 
1 , 875 
1,675 
200 
. 72 
62 
57 
3,950 
2,775 
1,175 
95 
82 
40 
2,450 
1,525 
925 
87 
65 
57 
4,000 
2, 400 
1.600 
100 
72 
47 
1,875 
1,800 
75 
75 
64 
77.. 
11,600 
7.050 
4,550 
137 
128 
47 
2,825 
1,725 
1 , 100 
90 
60 
79 
10, 800 
8,550 
2,250 
145 
102 
47 
2, 175 
1,300 
875 
71 
64 
