FOURTEEN TELEOSTEAN FISHES AT BEAUFORT, N. C. 
455 
Specimens 5 millimeters long. — The fish remains deep and compressed. The 
principal advancement over the 2.3-millimeter fish is the development of fins, for 
some of the anal, dorsal, and caudal rays are definitely formed. Posteriorly, the 
notochord is bent upward abruptly, giving the tail a pronounced heterocercal appear- 
ance. Preopercular spines are present but proportionately smaller than in younger 
fish. Chromatophores have increased in number, a few having appeared on the head, 
and some specimens have 3, others 4, longitudinal rows of black chromatophores on 
the side extending backward from the vertical|of the vent. |H (Fig. 69.) 
Specimens 7 milli- 
meters long . — The fish is 
much more regular in 
outline and more shape- 
ly than it is in the smaller 
sizes described. The 
concavity in the dorsal 
profile of the head, very 
pronounced in 2 and 3 
millimeter specimens, is 
very slight at this size. 
Figure 69 . — Decapterus punctatus. From a specimen 5.2 millimeters long 
The distal part of the tail has become deeper, much more 
shapely, and has lost its heterocercal character. However, the body remains deep and 
compressed. The fins are all developed. The ventrals are very small and were not 
noticed in smaller specimens. The vertical fins are fairly well developed. However, 
the spines in the dorsal and anal are scarcely distinguishable from the soft rays and 
the caudal fin has a round margin. Dark chromatophores have increased in number 
on the dorsal surface of the head. In other respects pigmentation remains much as in 
5-millimeter specimens. 
Specimens 10 millimeters long. — No pronounced advancement in the develop- 
ment, over 7-millimeter fish, is evident. The preopercular spines have become 
quite small, the 
mouth is noticeably 
less oblique than in 
the very young, and 
the dorsal outline of 
the head is regularly 
convex. The spi- 
nous dorsal is differ- 
entiated and sepa- 
rated from the soft 
dorsal by a notch. 
The spines in the anal 
fin too are well differ- 
entiated, and the caudal fin is slightly forked. A concentration of dark chromato- 
phores has taken place on the head, making a black blotch on the occipital surface. 
A black line on the middle of the side on the caudal portion of the body is now visible 
to the unaided eye. This dark line is very characteristic of the young and serves as 
an early recognition mark. (Fig. 70.) 
Specimens 15 millimeters long. — The head is disproportionately large and deep 
in the smaller fish, being notably deeper than the rest of the body. At a length 
of about 15 millimeters the greatest depth of the head is equal to the greatest depth 
Figure 70 . — Decapterus punctatus. From a specimen 10.5 millimeters long 
