FOURTEEN TELEOSTEAN FISHES AT BEAUFORT, N. C. 
403 
mentation. In fact pigfish have no outstanding color markings until a length of 
about 15 millimeters is attained, when a dark lateral band has developed. 
The young fish attains a length of about 2.5 millimeters within a day or so after 
hatching. (Figs. 25 and 26.) At this size the body has become quite straight, the 
pigment spots on ihe anterior part 
of the body at first present have 
become diffuse, but the ones over 
the vent and at mid-caudal length 
are verv distinct and form more FlGUEE 20. — OTthopristts chrysopterus. Larva 1 day old, ventral view. 
, . Actual length, 2.6 millimeters 
or less definite crossbars. In some 
individuals the spots behind the auditory canals still persist at this age. The yolk 
sac has decreased to somewhat less than a fourth of its original size, but the oil 
globule persists. At this size, or a little later, the fish begins to orient itself in part; 
that is, it no longer swims on its back but more or less on the side. (Fig. 27.) 
Usually by the third day at lab- 
oratory temperatures prevailing 
during May and June the yolk 
is nearly all absorbed, and gen- 
erally the oil globule, too, dis- 
appears about this time. The 
fish now has attained a length of 
about 2.8 millimeters, pectoral fins have become evident, and it is able to swim in 
the usual upright position. It may continue to live for several days longer (a few 
individuals have lived nine days) in the sediment jars used, but there is no further 
gain in size and little change in structure. (Fig. 28.) 
Specimens 3.1 millimeters long. — Specimens of this size are characterized chiefly 
by the long, slender tail, the vent 
Figure 27 —Orthopristis chrysopterus. Larva 2 l A days old; actual length, 
3 millimeters 
Figure 28 —Orthopristis chrysopterus. Larva somewhat older than the one 
represented in Figure 27, but actually a little shorter, 2.8 millimeters long. 
Note indication of fin rays within fin fold 
being situated well in advance 
of mid-body length, and by the 
almost vertical mouth, which is 
only moderately oblique in the 
adult. A pronounced hump is 
present dorsally just behind 
the eyes; the intestine is attached loosely to the body and distally more or less 
free. The fin fold is continuous, and the vertical fins remain undifferentiated. 
Pigment spots are wanting in preserved specimens. (Fig. 29.) 
Specimens 4-9 millimeters 
long. — The body, especially pos- 
teriorly, has become deeper; 
and the only other pronounced 
change since a length of 3.1 mil- 
limeters was reached is in the 
development of the caudal fin 
which now has become partly differentiated, rather definite rays having appeared ven- 
trally of the notochord. The notochord has curved upward somewhat, giving a hetero- 
cercal appearance to the tail, which is not as pronounced, however, in the pigfish as in 
several other species studied, especially in the croaker and the spot. (Fig. 30.) 
Specimens 6.7 millimeters long — ' The deepening of the body posteriorly continues. 
The caudal finis now rather well developed and has a round margin. The notochord 
Figure 29. — Orthopristis chrysopterus. Larva slightly further advanced than 
one shown in Figure 28. Actual length, 3.1 millimeters 
