REPRODUCTION AND DEVELOPMENT OF SCIAENIDAE 
59 
The present species, at a length of 10 millimeters, is intermediate of the other 
local species of the genus in the shape of the body, that is, the body is deeper and more 
strongly compressed (especially the head) anteriorly than in littoralis, and less so than 
in saxatilis. It also has a larger and an almost perfectly round disk-shaped pupil, 
whereas the pupil is vertically elongate and somewhat eliptical in littoralis and 
saxatilis. (The shape of the pupil often becomes somewhat distorted during preser- 
vation and, therefore, the difference in shape is not always as plainly evident in pre- 
served specimens as in fresh material.) The caudal fin is quite long and pointed and 
nearly symmetrical in americanus. In the other species this fin is quite broadly and 
asymmetrically rounded, the longest rays being in the lower half of the fin. In 
americanus the spinous dorsal often is partly black, while the ventral fins are color- 
less, or at most with only a few dark points. In saxatilis the spinous dorsal and the 
ventral fins are wholly black, whereas in littoralis these fins are colorless. 
Specimens 13 to 15 millimeters long. — The body has become less strongly com- 
pressed since a length of 10 millimeters was reached and has become deeper in the 
region of the vent, causing a notably less pronounced tapering in the depth from the 
head to the vent. The length and greatest depth of the body, however, remains 
proportionately about the same as in the 10-millimeter fish. The head is less com- 
pressed; the mouth is more nearly horizontal, and the snout now projects slightly 
beyond the upper jaw. The caudal fin has become proportionately longer and more 
strongly pointed. No other changes in the fins that appear to be worthy of note are 
evident. The color has changed little. The general tendency is toward fewer large 
branching cliormatophores and more numerous small dark points. The spinous dorsal 
and the anal are at least partly black; the second dorsal, the pectorals, and the caudal 
are unmarked, or the caudal at most may have a few dark markings on the base; and 
the ventral fins may have only a few dark dots or be solidly black at the base. 
The fish obviously has made fair headway toward the adult form in the shape of 
the head, the body, and the mouth. This species at the size just described differs 
from littoralis about as in the smaller fish previously described, that is, the body is 
deeper, the pupil is round, the caudal is longer and more pointed, the spinous dorsal 
is at least partly black, the soft dorsal is unmarked, and the ventral fins have at least 
some dark points if not partly black. No specimens of saxatilis between 11 and 17 
millimeters in length are at hand. Therefore, the exact differences between specimens 
of americanus arid saxatilis of this size cannot be stated at this time. 
Specimens 18 to 20 millimeters long. — The body lias continued to grow rather 
more elongate and rounder. The head remains somewhat deeper than wide, however, 
and the greatest depth (which occurred at the posterior part of the head in smaller 
specimens, now falls under the spinous dorsal) is contained 3.6 to 3.8 times in the 
length to the base of the caudal fin. The mouth is nearly horizontal and inferior, 
and the conical projecting snout is only a little shorter than the eye. A slight knob 
has appeared at the tip of the lower jaw, which is the beginning of the development 
of the characteristic mandibular barbel of the adults of the genus. Scalation is nearly 
complete (although not shown in the illustration). The caudal fin remains long and 
pointed. The longest rays now definitely occur in the lower half of the fin, and are 
somewhat longer than the head. Pigmentation has progressed rather rapidly. While 
variation is evident among specimens, most usually the entire body is spotted with 
black or dark brown. The spinous dorsal and the anal fins are largely black, as in 
smaller fish; the ventral fins bear dark spots; and generally two dark blotches have 
appeared on the base of the caudal fin (fig. 7). 
