Gillichthys mirabilis ■ — -BARLOW 
57 
Fig. 6. Fin rays in the first (spiny) and second 
(segmented only) dorsal fins, from left to right, pre- 
sented as a function of °N latitude. Materials and 
place names in Table 2. Large rectangle, one standard 
deviation on either side of mean (triangular promi- 
nence) ; blackened space, two standard errors on either 
side of mean; lower horizontal line, range of counts. 
Open rectangle, Pacific Coast populations; vertical lines 
in rectangle, Salton Sea population; oblique lines in 
rectangle, Gulf of California populations. 
populations overlap in the southern latitudes 
(Fig. 8). 
The average pectoral fin count of the Salton 
Sea fish again is much higher than in Pacific 
Coast animals. The number of fin rays, how- 
ever, is similar to that found in northern Gulf 
populations (Fig. 8). 
The Venice population, near Los Angeles 
on the Pacific Coast, is extremely variable. Some 
pectoral fins are deformed and obviously are 
aberrant. This habitat is polluted by sewage 
and industrial waste products. 
Combined Fin Counts 
Some of the trends and differences observed 
in the study of individual fins disappear when 
the fin counts are combined and plotted as a 
function of latitude (Fig. 9). At different lati- 
tudes the averages of the combined fin counts 
are about the same, except in California where 
a slight increase from north to south occurs. 
Otherwise there is no trend in the mean num- 
ber with latitude. When comparisons are made 
at the same latitudes, the Pacific Coast popula- 
tions and all of the Gulf populations, except 
for San Felipe, broadly overlap. Contrariwise, 
some divergences are enhanced. The Salton Sea 
and San Felipe populations are obvious deviants. 
Further discussion of combined fin elements 
is reserved for the section on annual variation. 
Fin Ray Variance 
Over the geographic range of mirabilis there 
are dissimilarities in the variances of each of 
the fins. The difference between the extreme 
variances of the first dorsal fin on the Pacific 
Fig. 7. Fin rays in the anal fin (segmented only) 
presented as a function of °M latitude. Materials and 
place names in Table 2. Large rectangle, one standard 
deviation on either side of mean (triangular promi- 
nence); blackened space, two standard errors on either 
side of mean; lower horizontal line, range of counts. 
Open rectangle, Pacific Coast populations; vertical 
lines in rectangle, Salton Sea population; oblique lines 
in rectangle, Gulf of California populations. 
