64 
PACIFIC SCIENCE, Vol. XVII, January 1963 
TABLE 7 
Relationship between the Pectoral Fin Rays and the Sum of the Segmented Rays of the 
Second Dorsal Fin and Anal Fin in Gillichthys mirabilis 
DORSAL PLUS ANAL 
SEGMENTED RAYS 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
San Eli jo Lagoon 
mean pectoral rays 
(n) 
20.0 
(9) 
20.0 
(10) 
20.0 
(9) 
20.0 
(2) 
Salton Sea 
1953 
mean pectoral rays 
(n) 
21.0 
(2) 
21.1 
(ID 
21.2 
(9) 
21.7 
(6) 
21.0 
(2) 
1954 
mean pectoral rays 
(n) 
21.5 
(17) 
21.1 
(8) 
21.2 
(6) 
1955 
mean pectoral rays 
(n) 
22.0 
(1) 
21.5 
(ID 
21.3 
(6) 
21.5 
(8) 
21.0 
(2) 
22.0 
(2) 
Bahia Cholla 
mean pectoral rays 
(n) 
21.0 
(1) 
20.0 
(1) 
21.0 
GO) 
21.0 
(15) 
21.0 
(3) 
Felipe. But in fish from the Salton Sea, the 
segmented rays of each of these fins are com- 
monly preceded by two, or occasionally three, 
spines. When two spines are present in the soft 
dorsal or anal, the anterior-most spine is short. 
Usually it is less than one-half the length of 
the first segmented ray. Sometimes it is difficult 
to find the anterior-most supernumerary spine. 
In the soft dorsal only, the first of three spines 
is always short (usually a stub) and sometimes 
does not reach through the skin, while the sec- 
ond usually is moderately well developed and 
may be greater than half the length of the first 
segmented ray. 
Supernumerary spines occur in the second 
dorsal fin more often than in the anal fin. In 
samples from 3 successive years (in each, n = 
30), the percentages of the fins with extra spines 
are: second dorsal = 40, 13, and 33; anal = 
10, 3, and 3. These data are from direct obser- 
vations. 
Photographs with X-rays revealed the pres- 
ence of additional spines beneath the skin and 
of their basal elements. In one collection (n = 
30, from 1955, but a different sample than the 
one mentioned in the preceding paragraph), 
53% of the specimens have two spines in the 
soft dorsal and 10% have three (total =z 63%). 
In the same sample, 13% of the fish have two 
spines in the anal fin, but none have three. 
The situation is further complicated in that 
the number of spines does not always agree 
with the number of basals. Three specimens 
with only one spine in the fin have two basal 
elements. There is an additional basal anterior 
to the basal of the first, and only, spine. In two 
specimens, on the other hand, two spines share 
a single basal. In these cases, the first spine is 
merely a stub. In the specimens with three 
spines, three basals are found. Generally, ele- 
ments are added anteriorly onto the anal fin, 
and especially the soft dorsal fin. This is done 
either by adding spines, basal elements, or both. 
Axial deformities are conspicuous in fish 
from the Salton Sea (Fig. 13). Mostly they are 
situated anterior to the origin of the second 
dorsal fin. These are predominantly direct dorsal 
flexures, but may tend to right or left. Posterior 
to the first dorsal fin, the flexures are divided 
about equally between dorsal, lateral, and ven- 
tral. A few specimens have severe lateral flexures 
in the hypural plate (Fig. 13). More than one 
