Gillichthys mirabilis— Barlow 
63 
the test of the sample with the larger fish ap- 
parently causes the significant differences be- 
tween the groups. Hence the differences between 
the three year classes seem to be caused by 
unequal size groups. 
Peculiarities of G. mirabilis from the Salton Sea 
The mirabilis introduced into the Salton Sea 
differ from naturally occurring populations in 
several ways. Most of these differences seem 
to indicate an interference with the normal de- 
velopmental physiology. 
Some of the unusual features of the Salton 
Sea fish have already been discussed in earlier 
sections, and they are enumerated below. All 
the counts of fin rays and vertebrae are higher 
in these fish than in any others. The relation- 
ship between the fin ray numbers as reflected by 
the fin index, however, has remained the same 
as that of the parental stock. The squamation is 
less extensive, and the head and upper jaw are 
disproportionately small. The formation of the 
interorbital pore is delayed. 
The Salton Sea fish differ from naturally oc- 
curring forms in still other ways not yet de- 
scribed. The otoliths are much coarser and more 
opaque than those of specimens from the outer 
coast. The outline of the otoliths, as seen from 
either flat side, is less angular and is often al- 
most round. The edges of the otoliths usually are 
only weakly crenulate or smooth, and the char- 
acteristic notch is indistinct. 
In gobiid fishes, the segmented rays of the 
soft dorsal and anal fin typically are preceded 
by one slender spine. This holds for mirabilis 
in naturally occurring populations, with rare 
exceptions. Supernumerary spines, however, 
have been found on two specimens of mirabilis 
from San Eli jo Lagoon and one from Newport 
Bay, and also on one specimen of seta from San 
TABLE 6 
Annual Variation of Fin Counts of Gillichthys mirabilis 
(Key: x, mean; s, one standard deviation; r, range.) 
COLLECTED 
SALTON SEA 
GULF OF CALIFORNIA 
NW Shore 
18 July 
1953 
NE Shore 
17 July 
1954 
NW Shore 
13 July 
1955 
Bahia Cholla 
27 January 
1949 
Bahia Cholla 
27 April 
1954 
Size range in mm 
55-109 
40-78 
35-74 
20-30 
48-82 
n 
30 
30 
30 
30 
30 
First dorsal 
X 
6.23 
6.27 
6.27 
6.07 
6.07 
±s 
0.504 
0.451 
0.521 
0.255 
0.253 
r 
(5-7) 
(6-7) 
(5-7) 
(6-7) 
(6-7) 
Second dorsal 
X 
12.43 
12.33 
12.57 
11.33 
10.37 
±s 
0.679 
0.547 
0.679 
0.480 
0.555 
r 
(11-14) 
(12-14) 
(11-14) 
(11-12) 
(9-11) 
Anal 
X 
11.27 
11.33 
11.60 
9.60 
930 
±s 
0.583 
0.480 
0.814 
0.564 
0.702 
r 
(10-12) 
(11-12) 
(11-14) 
(9-11) 
(8-11) 
Pectoral (left) 
X 
21.33 
21.33 
21.47 
21.30 
20.97 
c±S 
0.679 
0.480 
0.628 
0.625 
0.616 
r 
(20-23) 
(21-22) 
(20-22) 
(20-23) 
(20-22) 
Combined 
X 
74.93 
74.67 
75.70 
71.73 
69.67 
±s 
1.68 
1.18 
1.95 
1.53 
1.65 
r 
(72-79) 
(73-77) 
(71-80) 
(69-76) 
(66-72) 
Index 
X 
112 
111 
113 
98 
94 
