828 PROFESSOR W. C. MINTOSH AND MR E. E. PRINCE ON 
Rudely stellate (¢.e., with short rays) black chromatophores appear on the seventh 
day (May 4), on the dorsal surface of the trunk. The vesicles on the ventral surface 
still persist along with Kuprrer’s vesicle. About thirty somites are visible, and the 
caudal plate rises prominently upon the yolk. The otocysts are also present and have 
a circular outline. The heart is being differentiated from a protruding mass of cells 
below the otocysts, and folds immediately behind indicate the mesenteron. ‘The oil- 
globule projects from its pocket in the yolk, externally having a covering of blastoderm. 
A central fissure occurs in each eye. 
Eighth Day.—Vhe tail is well formed and is laterally flexed on the yolk. The finely 
branched chromatophores form two somewhat regular dorsal lines, and five or six solitary 
spots also occur over the yolk, in its outer envelope. The cardiac pulsations are faint. 
The nasal bulbs are distinct, and the lenses of the eyes fully formed. Very delicate 
round pigment-spots of a pale greenish-yellow colour appeared about noon, giving the 
ovum a slightly greenish tint to the naked eye. These greenish-yellow corpuscles were 
thickly scattered at the ventral margin, and especially on the marginal fin, almost to 
the tip of the tail. Each segmental duct ends in a space above the end of the intestine, 
and the anal tract sends a protoplasmic tube partially across the tail-fin, The lumen 
has an external opening on one side of the caudal fin-membrane. 
Next day (6th May) the embryos (PI. XIII. fig. 4) emerged, though some which 
had been isolated in a small quantity of sea-water in a room escaped the previous day. 
They measured about 3 mm., the yolk being 1 mm. in its long diameter. They appeared 
to be delicate, many lying on the bottom, while the more active floated in the reversed 
position near the surface, and were able to wriggle a little. The liver appears to be 
further back than in the other Gadoids examined, the distance being nearly one-fifth the 
length of the head and trunk (excluding the tail). The fine lumen of the mesenteron 
extends to the opening formerly indicated. Anteriorly it ends as a fine fissure behind 
the heart. About fifty myotomes are marked off, and the caudal trunk terminates in a 
slight enlargement. The otocysts have thick walls, and just in front of them are two 
clefts. The heart slowly pulsates. The finely stellate chromatophores in the caudal 
region seem to correspond in number to the lines of the metameres. 
The larvee on the 7th May presented certain peculiarities at the tip of the 
notochord very distinctly, viz., a slight enlargement followed by a constriction, then a 
large swelling in front of the terminal knob. The lumen of the intestine was slightly 
increased, though still smaller than the mesenteron proper. The urinary vesicle (which 
communicated with the rectal portion of the canal) showed continual movement of its 
walls. The yolk-cortex has receded considerably from the outer envelope (blastoderm) 
leaving a large extra-vitelline space, and the oil-globule (og) is also lifted away from 
the outer layer. The distance of the heart and the oral region from the liver is still 
marked. The heart, on the 8th May (Pl. XVII. fig. 9), was much flexed, asuming an 
S shape, but no definite wall to the pericardial chamber was visible. The yolk has 
diminished. On the 10th May large ramifying chromatophores occur over the yolk, 
