DE VELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
635 
both on tlie embryo and the yolk. Note that few oil globules, most of them being 
small, are present. This again is not characteristic of this stage, but only of the 
particular egg drawn. 
Newly hatched larvae . — The newly hatched fish is only about 1.7 to 1.9 mm long. 
The dorsal and ventral finfolds are very wide, making the larva seem short and deep. 
The head is slightly deflected, and on its 
dorsal surface is a pronounced hump. The 
tail is straight and pointed. 
The yolksac is comparatively large and 
some or all the oil globules present in the 
egg are retained. The number of globules 
in the yolksac is equally as variable as in 
the egg. The yolksac also retains the green 
specks and cliromatophores described for 
the eggs in advanced embryonic stages. 
Green specks also are present on the 
body of the larva, except on the distal part 
of the tail. On the vertical finfolds green 
specks are concentrated to form blotches, 
which are somewhat variable among indi- 
viduals in size, intensity, and position. 
There is one on the dorsal finfold above 
the yolksac; another on the fold above the 
vent; generally a more or less definite corresponding one on the ventral finfold just 
behind the vent; and another pair on the fold at about mideaudal length. In some 
individuals the concentration of color is continued more or less on the body of the 
larvae, forming indications of cross bars, which become more distinct as the fish grow. 
In addition to the green specks more or less definite dark chromatopliores are variously 
distributed over the body and finfolds. 
Heart action is visible, but due to the opaqueness of the fish the circulation cannot 
be seen. The vent is located at about midbody length. The newly hatched fish 
swims, or floats on its back, presumably being held in that position by the bouyancy 
of the many oil globules in the yolksac (fig. 151). 
Figure 150. — Achirus fasciatus. From egg with rather 
advanced embryo. 
