2 66 
California State Fisheries Laboratory, who has 
examined the skeletons of four adults identified 
from Kishinouyes description as E. line atm. 
He has sent us the following data regarding 
these specimens, the first three of which were 
from tuna-clipper landings from unknown 
points somewhere south of the Mexican border, 
and the fourth of which was captured off Espi- 
ritu Santu Island in the Gulf of California: 
Specimen number........... 12 3 4 
Vertebra bearing 1st haemal 
arch.................................... —- 16 15 16 
Total vertebrae (including 
urostyle...... 37 39 37 37 
Abdominal vertebrae..... —- 21 19 20 
Caudal vertebrae.................... 18 18 17 
Three of these four specimens have 37 
vertebrae, corresponding with our juveniles, 
and disagreeing with Kishinouye. Mr. Clothier 
has also advised us that, in addition, H. C 
Godsil of the same laboratory, has examined 
two specimens - from near Magdalena Bay each 
of which had 37 vertebrae. It appears that E. 
lineatus has 37 vertebrae as a rule. The verte¬ 
brae counts of our juveniles agree, then, with 
those of adult E. lineatus identified from other 
characters. All other characters examined 
agree well enough with Kishinouyes descrip¬ 
tions, and it was therefore concluded that these 
were juveniles of E. lineatus. 
There are few references to juvenile Euthyn- 
nus in the literature. Kishinouyes (1923: 388) 
smallest specimens, 13 cm. in length, from the 
Asiatic side of the Pacific, were larger than any 
of ours. He described them as follows: "They 
are very slender and have eight or more trans¬ 
verse bands on the side. These bands are nearly 
vertical and fade toward the ventral median line. 
When they grow to a total length of 19 cm. 
the body becomes very broad, the thoracic spots 
appear, the bands gradually disappear from the 
ventral part and the dorsal part of the bands 
becomes oblique.” 
Ehrenbaum (1924) found among the Medi¬ 
terranean collections of the Danish Oceano¬ 
graphical Expeditions six young tunas, 5.9 to 
PACIFIC SCIENCE, Vol. II, October, 1948 
10.1 mm. in length, which he referred to 
Euthynnus alliteratus (Raf.). He differentiated 
these specimens from those of Auxis thazard 
only with great difficulty, on the basis of the 
first dorsal rays. The identification seems doubt¬ 
ful, but, since none of our specimens of Eu¬ 
thynnus are as small as Ehrenbaum’s, we can¬ 
not verify it. 
Auxis thazard (Lacepede) 1802 
As is the case with many of the scombroids, 
there is some doubt as to whether there is a 
single cosmopolitan species of Auxis or whether 
different species occur in different parts of the 
world. The solution of this problem is be¬ 
yond the scope of this paper and our juveniles 
are referred to Auxis thazard. No adult speci¬ 
mens were examined by us during this voyage, 
but the capture of juveniles indicates that this 
species spawns in Central American Pacific 
waters during the early spring. Juveniles were 
taken at the following stations on the dates 
indicated: 08° 20' N., 84° 10' W.; March 18, 
1947; 2 specimens, 67 and 68 mm. total length. 
09° 43' N, 85° 54' W.; March 19, 1947; 52 
specimens, 21 to 53 mm. total length. 08° 7' 
30" N., 83° 8' 30" W.; May 7, 1947; 3 speci¬ 
mens, 23 to 41 mm. total length. 09° 43' N., 
85° 54' W.; May 17, 1947; 1 specimen, 42 mm. 
total length. Through the courtesy of Dr. J. T. 
Nichols, we were also able to examine 5 speci¬ 
mens, 22 to 31 mm. in total length, taken 
under a light at night from the "Askoy” at 
04° 01' N., 80° 26' W. on March 24, 1941. 
Nichols and Murphy (1944: 241) suggest that 
these may be young Euthynnus , but they are 
undoubtedly Auxis. 
Representative specimens of juvenile A. 
thazard are shown in Figures 3 and 4. In the 
smaller specimens the prominent areas of pig¬ 
mentation are on the upper and lower jaws, 
above the snout, around the postero-ventral 
margin of the orbit, on the upper operculum, 
between the orbits, along the mid-line of the 
body, along the bases of the dorsal and anal fins 
