THE LIFE-HISTORY OF THE PILCHARD. | 151 
hatched from it differed in no respect from those hatched from 
normal eggs. 
These pilchard eggs were placed in a glass hatching jar in one of 
the laboratory tanks, and treated in the way described in my Treatise 
on the Sole. The temperature of the water was 17°C., and its 
density, 1026°5. The eggs all hatched on September 7th, only three 
days after fertilization. The newly-hatched larve agreed exactly 
with Fig. 30, plate 5 of Vol. I of this Journal. The larva is 3°8 mm. 
in length. Fig. 2 shows the appearance of the living larva seen 
from above in its natural position, floating with the yolk-sac upper- 
most. In this position little protuberances are seen on each side of 
the body; these are larval sense organs, such as are seen in the 
larvee of fishes generally, and from them are derived the sense organs 
of the lateral line, but in the adult pilchard these sense organs are 
wanting, so that the larval sense organs evidently disappear during 
development. 
When the larva is first hatched the yolk is large, the mouth not 
open, and there is no pigment, except a few black chromatophores 
along the dorsal region of the body. The yolk diminished on the 
second day, September 8th, and on the third day, September 9th, 
the mouth was found to be open as a wide rhomboidal aperture on 
the under surface of the head. A little yellow pigment and reflecting 
substance was now present in the eye. 
On the 10th, by the growth of the lower jaw and under parts of 
the head, the mouth had become terminal ; the eyes were black and 
opaque, and there were black chromatophores along the sides of the 
body ventrally. The yolk was reduced to a very small remnant, and 
with the absorption of the yolk the head region had become much 
shorter in comparison with the rest of the body. On this day I 
tried to feed the larvee with minute particles obtained from minced 
worms, but they took none of it. 
On the 11th I gave them some of the minute organisms obtained 
by the tow-net, and also a little more of the worm food, and, on exa- 
mining some of the larve, saw some of the food in the intestine. 
The food was particles of worm. 
On the 12th, when the larve were five days old, they were 5°5 mm. 
in length, the yolk was all gone, and they continued to feed on the 
particles of worm. Although I had the finest tow-net used, and put 
the produce into the jar containing the larve, none of it was ever found 
in their intestines. The tow-net produce included minute Peridinide, 
diatoms, worm larve, &c., which I thought probably formed the 
natural food of the larvee, but they did not feed on it, On the 14th 
there was evidently a diminution in the number of the larve, and I 
found that some had died and fallen to the bottom of thejar. During 
