Juvenile Tunas—SCHAEFER and Marr 
269 
specimen is shrunken from the preservative so 
that the spines project above the dorsal profile. 
In adult Auxis from Culion, Philippine Islands, 
examined through courtesy of Dr. G. S. Myers 
of the Stanford University Natural History 
Museum, the interneural supports of the sup¬ 
pressed rays are well developed; the rays them¬ 
selves are vestigial, however, and can be found 
only by staining and dissection. Fin ray counts 
on our stained juvenile specimens are as fol¬ 
lows: 
Total length of specimen...... 
mm. 
25 
mm. 
31 
mm. 
46 
First dorsal...... 
11 
11 
11 
Dorsal interspace...... 
6 
7 
8 
Second dorsal....... 
12 
11 
11 
Dorsal finlets...... 
8 
8 
8 
Anal............. 
14 
13 
13 
Anal finlets. 
7 
7 
7 
Ventral..... 
7 
7 
7 
Pectoral.... 
22 
23 
25 
Other, unstained, specimens 
also 
have eight 
dorsal finlets and seven anal finlets. In the 
smaller specimens the finlets are joined by a 
membrane that extends completely or nearly 
to their distal ends. With increasing size this 
membrane becomes less prominent until in our 
longest specimens it is wanting or exists only 
between the bases of the finlets. 
In all our specimens, each side of the upper 
jaw bears about 20 small, conical teeth; each 
side of the lower jaw about 25 small, conical 
teeth; each palatine 6 or 7 teeth; and the 
vomer none. The vomer and palatines are ex¬ 
posed. Starks (1910: 97), with reference to 
Auxis thazard, and Kishinouye (1923: 460), 
with reference to the genus Auxis, state that 
there are no palatine teeth, and this is apparent¬ 
ly true in the adults. In the two adults from 
Culion, Philippine Islands, the vomer and pala¬ 
tines are toothless and are not exposed. These 
specimens are probably Auxis hvra Kishinouye. 
The gill rakers on the most anterior gill arch 
of our smallest specimens are very tiny pro¬ 
jections and are difficult to count. They are first 
apparent near the angle of the arch. With an 
increase in the size of the fish, the rakers near 
the angle of the arch increase in length and 
new rakers are added distally on each arm. 
The full complement of rakers is apparently 
attained at about 50 mm. total length, as 
judged by the following counts on specimens 
of various sizes: 
21 
mm. 
4 
+ 
18 
24 
mm. 
5 
+ 
21 
27 
mm. 
6 
+ 
24 
32 
mm. 
9 
+ 
26 
42 
mm. 
9 
+ 
30 
46 
mm. 
10 
+ 
31 
52 
mm. 
12 
+ 
36 
54 
mm. 
11 
+ 
35 
68 
mm. 
11 
+ 
31 
Gill raker counts on the adult specimens re¬ 
ferred to above are 12 + 34 and 11 + 32. 
Kishinouye (1923: 462-3) gives 9 + 30 as the 
gill raker count for A. hira and 10 + 36 as the 
count for A. mam Kishinouye. Possible varia¬ 
tion in these counts is not mentioned. He does 
not list A. thazard, but A. mam is probably 
a synonym of A. thazard, as he tentatively sug¬ 
gests in his synonymy. 
The nasal rosette is visible only in cleared 
specimens. 
The vertebrae were counted as 20 + 19 (in¬ 
cluding the urostyle) in three cleared and 
stained specimens. This agrees with Kishinouye 
(1923: 452) and Frade and deBuen (1932: 
70), but disagrees with Starks (1910: 97), 
who counted 22 + 15 vertebrae. On a speci¬ 
men 46 mm. total length, small ventral fora¬ 
mina are present on the 9th to 15 th caudal 
vertebrae. On smaller specimens of 25 and 31 
mm. total length, these foramina are not dis¬ 
cernible, if present. In our specimens, the 
pedicles (of Starks = epihaemal process of 
Kishinouye) of the caudal vertebrae, bearing 
the closed haemal arches, are extremely short 
or non-existent. In a specimen of 25 mm. total 
length, the haemal arches of the caudal ver¬ 
tebrae are long, wide, and elliptical. In a speci¬ 
men of 46 mm. total length, the haemal arch 
