127 
EXPLORATIONS IN WESTERN CANADA, ETC. 
EX'fENT OF VARIATION BETWEEN THE PACIFIC SLOPE SPECIES OF THE 
DIFFERENT FAMILIES AS COMPARED WITH THE ATLANTIC SLOPE SPECIES 
OF TPIE SAME FAMILIES. 
Utilizing the data contained in tlie detailed lists in the x>receding chapter, we 
obtain the following: 
families bavin;;' both Atlantic and Pacific Slope species. 
raeiHc 
■slojie. 
Atlantic slope. ' 
Dorsal. 
Anal. 
I>orsal. 
Anal. ' 
1 
Acipenseridaa : 
nis;liest iiumlier of i-avs - 
48 
30 
41 
27 
Lowest number of rays 
33 
22 
35 
22 
1 Extent of variation 
15 
8 
(3 
s 
Catostomiiiae :*■ 
15 
13 
10 
10 
3 
CyprinidiB: 
Ui;;liest number of rays 
11 
'22 
10 
u 
Lowe.st number of rays 
8 
7 
7 
8 
Exteut of vai-i.-itioii 
3 
15 
3 
8 
Salmonidfe : 
Highe.st number of rays 
12 
17 
20 
tl5 
Lowest number of rays 
0 
9 
U 
9 
Extent of Tariation 
3 
8 
9 
0 
Cyprinodontidie : 
Hii;liest number of rays 
13 
15 
17 
15 
Lowest number of rays 
7 
7 
Extent of variation 
G 
8 
10 
*For obvious reasons snbfanulies of Catostoinidce not fomid in Pacilic Tvators are not taken into consideration, 
t Or if we leave out of consideration Thyuiallu^, we obtain dorsal 13 ; anal 11. 
In the following spiny-rayed fishes the combination of highest number of spines 
and rays need not occur in the same species: 
Families having both Atlantic and Pacific Slope species. 
Pacific slope. 
Atlantic slope. S 
Dorsal. 
Anal. 
Dorsal. 
Anal. 
Gasterosteida;; 
Pygo-steus— 
Highest number of spines and rays 
X, 1,10 
1, 10 
IX, I, 9 
I, 8 
Gasterostens — 
Highest number of spines and rays 
Lowest number of spines and rays 
IV, 13 
111,10 
I. 10 
I. 7 
III, 13 
III, U 
I, 10 
I, 8 
I, 3 
p 
•> 
IV, T. 10 
T 10 
IV, 11 
I, 8 
VIII, 3 
3 
V.TI, 4 
2 
Oentrarcbidfe (only a single specimen found on Pacific sloxie). 
Cottidas: 
X,20 
VII, 15 
18 
VIII, 18 
VI, 15 
14 
12 
11 
Extent of variation 
1 
III, 5 
0 
II, 3 
3 
