of the Fishery Board for Scotland. 
329 
Moreover, some appear on the surface of the yolk-sac. The heart 
pulsates. The free portion of the tail is considerable. 
14th July. The heart (which forms a transverse tube) exhibits more 
active pulsations. Only yellowish chromatophores are yet visible on the 
trunk and yolk-sac, though one or two along the lateral region seem to be 
blackish (PI. X. fig. 4). Under a lens the posterior region of the trunk 
and the caudal region have a median band of yellow pigment-grains, as 
well as a lateral line on each side, the latter being traced forward to the 
head.* The skin of the broad tail is minutely papillose or vesicular. 
Two escaped to-day from the capsule, i.e., towards the end of the 
6th day. 
15th July. Many have escaped to-day (PI. X. fig. 5), the laiva having 
the length of about 3*5 to 4 mm. It is distinguished by the great length 
of the yolk-sac in proportion to its depth, and by the peculiar curvature of 
the head from above downward and forward. A considerable number of 
dull gamboge-yellow pigment-grains occur along the edge of both dorsfil and 
ventral marginal fins — dorsally from the head to the tail, though not 
quite to the end of the latter, a portion being pale ; ventrally from the 
anus as far as a vertical line from the dorsal granules, and thus the series is 
short. The head and trunk are faintly yellowish from minute specks of 
the same pigment, and many occur on the yolk-sac. Under a moderate 
power very finely ramose black pigment is observed in connection with 
the yellow, and between and in the intermediate spaces on body, fin, and 
yolk-sac. The yellow pigment is not bright ; indeed, in the egg it appears 
a dull greenish yellow {vide PI. X. fig. 4). Cunningham's examples hatched 
on the 7th or 8th day in April, so that those at St Andrews escaped some- 
what earlier, as might have been expected from the temperature in July. 
During the next day or two (the 16th July) the young fishes show 
under a lens some touches of greenish yellow on the trunk behind the 
head (PL XI. fig. 1). Besides these are others on the marginal fin, the 
yolk-sac, and the head. The yolk-sac has now considerably diminished, 
and they swim on edge. 
On the 1 8th the pigment of the marginal fin is light yellow, while that 
of the trunk is dull greenish-yellow (probably from a greater development 
of black). The yolk forms but a small patch in front of the rectum 
(PI. XI. fig. 2). The eyes are silvery, and the fishes are active and sensi- 
tive. When swimming on edge, the larval fish, when viewed from above, 
is attenuate (PI. XI. fig. 3). 
19th July. The yellowish pigment in the marginal fin is even in 
greater contrast to the pigment on the body, which is now duskier 
from the development of black pigment over the yellow. To-day the 
last remnant of the yolk is a small round globule in front of the 
rectum, and it may be noted that in several a small vesicle resembling 
an oil-globule appeared in the middle of the diminishing yolk-mass. 
The branchiae are fairly formed, and the mouth gapes — without, how- 
ever, any movement of the jaws. A communication seems to be estab- 
lished between the mouth and the gullet. The otocysts almost touch 
the eyes. The liver forms a considerable mass in the anterior region of 
the abdomen. The pectorals are large and fan-like, and in swimming 
vibrate with great rapidity, while the head is often directed downward 
so as to reach the bottom of the vessel — as in the plaice. The marginal 
fin remains deep as in the pleuronectids generally. Five dark greenish- 
yellow spots occur, viz., the patch at the pectoral, one at the gut, 
and three at the region behind the vent. The species, however, is not 
* The yellow pigment eeems the more prominent in these, the black in 
Cunningham's. 
