50 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
A very marked change takes place in the shape of the caudal. In the adult the 
margin of the caudal is distinctly concave or lunate. In all stages of the young, on 
the other hand, the caudal rays between which the lateral line extends are the longer, 
the caudal being obtusely pointed, with 9 rays in the upper and 8 in the lower lobe. 
The upper lobe of the caudal is slightly lunate, while the rays of the lower lobe are 
graduated, and this lobe is rounded. 
Very marked changes take place in the color with age. The changes occur 
largely in the sides of the body. The color pattern of the head changes little with 
age. There is here chiefly an addition of color cells to those already present in the 
Figs. 1 and 2. — The left and right sides, respectively, of a specimen 200 mm. long taken September 7, 1900, in the Commis- 
sion’s net in Vineyard Sound. The left side shows the characteristic markings of the adult which are due entirely 
to the color in the outer layer of the skin. The nearly uniform distribution of color in the deeper layer of the skin 
seen after removal of the outer skin is represented in Fig. 2. This deeper layer of color no longer enters into the general 
coloration owing to the formation of connective tissue between it and the outer layer. 
smallest specimens. In the smallest specimen there is a series of four pigmented 
bands, extending across the back. The first at the spinous dorsal, the second at the 
beginning of the soft dorsal, the third some distance in front of the end of the soft 
dorsal, and the last across the caudal peduncle. All of these extend but little beyond 
the lateral line. Their margins correspond roughly with the margins of myotonies. 
At the dorsal angle of the myotonies the bands are usually bent, but without regu- 
larity. In the specimen under discussion, those on the left side are shifted backward, 
at this point, of those on the right side; two are continued straight down, one is 
shoved forward and the other backward. The region between the bands is not free 
