460 
BULLETIN OF THE BUREAU OF FISHERIES 
are at hand and, therefore, the development of the intermediate sizes can not be 
traced at this time. 
Specimen 2.9 millimeters long. — The larva at this size is quite compressed, the 
head is deep, the mouth is slightly superior and strongly oblique, and a very pro- 
nounced angle in the ventral outline of the head is formed at the joints or hinge of the 
mandible. The eye is small for so young a fish and is scarcely longer than the snout. 
The abdomen is moderately prominent, and the vent is situated near mid-body 
length. The dorsal profile is quite convex, except for a slight concavity just in 
front of the eye. The tail tapers gradually and ends in a sharp point. Pectoral fin 
folds are rather prominent but no ventral fin folds are in evidence. The vertical 
fin folds either have been 
torn away or are very low. 
The specimen is rather dark 
in color and the only pig- 
ment spots evident in a 
preserved specimen are a 
few indefinite ones on the 
ventral outline. (Fig'. 73.) 
Young of this size re- 
semble Decapterus pundatus 
somewhat; but the head is not quite as deep in comparison with the body, the snout 
is not curved upward to the same extent, the eye is proportionately much smaller, 
preopercular spines are wanting (although present at a somewhat larger size), and fin 
development has not progressed quite as far. (Compare figs. 68 and 73.) Another 
distinction is the absence of color markings along the dorsal outline in Seriola. 
Specimens 5 millimeters long. — The body remains quite compressed as in smaller 
specimens. However, anteriorly it is not as deep as previously in proportion to the 
total length, and the tail, especially distally, is much deeper. The mouth is less 
strongly oblique, and the sharp angle at the joints of mandible, present in smaller 
specimens, has disappeared, the ventral outline of the head now becoming evenly 
convex. Fin rays are not 
yet very evident, except in 
the caudal fin. The noto- 
chord extends prominently 
into the upper part of the 
caudal fin giving the tail a 
decided heterocercal appear- 
ance. Pigmentation in the Figure 74 .— Seriola dumeriU. Drawn from a specimen 4.7 millimeters long 
most distinctly marked spec- 
imens consists of a very narrow dark lateral stripe in addition to some large dark 
chromatophores irregularly distributed over the body. In some specimens the mark- 
ings are much more diffuse than in the specimens described. (Fig. 74.) 
The absence of preopercular spines, the more regular dorsal outline of the head, 
and the less strongly oblique mouth distinguish this species from the scad at this 
size. The large black chromatophores on the side of the abdomen behind the base 
of the pectoral, too, are helpful, especially since the other color markings are largely 
similar to those of the scad of the same size. 
Specimens 6 millimeters long. — The fish at this size have comparatively large 
spines on the preopercular margin (which disappear at a somewhat larger size). 
Figure 73 . — Seriola dumerili. Drawn from a specimen 2.9 millimeters long 
