Gillichthys mirabilis — Barlow 
71 
4. The scales are larger and the ventral area 
more scaled in specimens from the Gulf than 
in those from the outer coast. Scalation is notice- 
ably reduced in fish from the Salton Sea. 
5. Trends in means of meristic characters, 
from north to south along the Pacific Coast, 
and then from south to north up into the Gulf 
of California, are as follows: spiny dorsal fin — 
no change or slight increase; segmented rays of 
median fins — decrease; pectoral fin — increase; 
combined fin elements — irregular or no change; 
fin index (segmented dorsal plus anal rays, di- 
vided by pectoral rays, times 100) — decrease; 
pectoral fin asymmetry — -decrease; vertebrae — 
no change. 
6. The variance of the number of elements 
in each fin is a function of latitude, greater vari- 
ance being associated with higher latitudes. 
7. The means of the counts of the median 
fin are negatively correlated with the means for 
pectoral fin rays when the comparison is be- 
tween the various populations. In successive 
year classes within a given population, however, 
changes in the number of rays in the median 
fins are associated with commensurate changes 
of the same sign in the counts of the pectoral 
fin rays. But within each year class there is no 
correlation between the number of pectoral fin 
and median fin rays. 
8. All meristic characters have higher mean 
values in specimens from the Salton Sea, but 
the mean of their fin index accords with the 
Pacific Coast population from which they were 
derived. The Salton Sea fish are aberrant in 
many ways, evidently as a result of living in a 
marginal environment. 
9. The conclusions based on these findings 
are condensed on the last page of the foregoing 
article. 
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