of the Fishery Board for Scotland. 
293 
following day (30th May) the embryo was fully half round the yolk (PI. 
XVI. figs. 3 and 4) and the perivitelline space had increased. The lenses are 
now present, and black chromatophores appear in the caudal region and 
under the oil-globule. 
On the 31st the increase of the perivitelline space was more marked than 
on the 30th — from the diminution of the yolk, the tail of the embryo pro- 
jects as far as the oil-globule, and the black chromatophores of the tail 
are conspicuous, and have commenced to ramify. Black pigment appears 
along the sides of the embryo. The chromatophores under the oil- 
globule are more numerous, and are minutely branched. The otocysts 
are visible, and the heart exhibits faint contractions. 
At 4 p.m. on the 1st of June two larvae were hatched — it may be some- 
what prematurely. The larva (PI. XVI. fig. 5) possesses only black pigment, 
which is somewhat uniformly scattered over the body, with a few specks 
on the head. The black chromatophores also occur, both dorsally and 
ventrally, in the marginal fin. Thus five or six V-shaped chromatophores 
are found near the margin of the dorsal fin behind the yolk-sac, almost 
intermediate between it and the tip of the tail, and two similar or some- 
what triangular ones are present ventrally, opposite the former. The large 
oil-globule lies at the posterior and inferior part of the yolk, and has the 
usual black chromatophores. The otocysts are simple sacs. No pigment 
exists in the eyes. The notochord is distinctly multicolumnar. The 
solid strand of the rectum comes to the edge of the marginal fin, and a 
pre-anal portion of this fin occurs between it and the yolk. The urinary 
vesicle shows only a small central chamber. 
Next day other larvae appeared, some considerably more vigorous than 
those of yesterday. They float with theyolk-sac uppermost (PI. XVI. fig. 7), 
and have only black pigment. The oil-globule in lateral views is some- 
what elliptical (PL XVI. fig. 6). 
On the 3rd June yellow pigment was apparent amongst the black in 
the marginal fin, and also along the sides of the body posteriorly. None 
was present on the head. The yolk-sac has, as a rule, no pigment- 
corpuscles, only one or two black chromatophores appearing occasionally 
at the upper part of the region. 
The enlargement of the otocysts, liver, and other organs is considerable, 
and the skin is assuming a minutely vesicular condition. In larvae which 
only escaped from the capsule to-day the yellow pigment was noticeable 
on the caudal region on extrusion. In these, as in other species, the diffi- 
culties of hatching are increased by the emergence of the tail first, as the 
zona clasps the yolk and prevents its exclusion. Some die in this position. 
The capsule (zona) retains the ridges and lines after hatching has taken place. 
The mouth in this species seems to open comparatively early, and on 
the 6th June it formed a conspicuous aperture, as shown in the dead 
example sketched in PI. XVI. fig. 9. It is more anterior in a living 
specimen, as the parts have been drawn backward. The under surface of 
the head in many views has a tuberculate appearance from the lateral 
processes of the opercula. Three arches are observed through the 
branchial aperture. The shape of the head is also peculiar. The 
pericardial chamber is very large, so that the heart seems to be further 
back than usual. The yellow pigment has largely increased along the 
muscle-plates, pre-anal region, and elsewhere. 
On the 7th June black pigment was developed in the eyes. The oral 
aperture differs considerably from that in the gadoids, since the man- 
dibular cartilages are much less developed, yet the aperture is proportion- 
ally large and the movements extensive. The yolk has diminished. The 
opercular eminence (PI. XVI. fig. 8), gill-aperture, and branchial arches 
