194 Prof. M'Intosh's Notes from the 



from the male organs of most of the gadoids. The ovaries, 

 on the other hand, are large. 



On the fourth day (25th May) the blastopore was closing 

 or closed, the optic vesicles formed, and a broad alar expan- 

 sion extending outward on each side. A small perivitelline 

 space is present. 



Before hatching a greenish-yellow hue by transmitted light 

 appeared on the head and on the tip of the tail. The larva 

 measures about 4 millim., and is characterized by the large 

 pinkish-brown oil-globule which is generally fixed at the 

 posterior border of the yolk. In some the oil-globule, how- 

 ever, is freely movable, and by depressing the tail of the 

 larva it glides forward to the middle of the yolk, while by 

 elevating the head it mounts to the highest point, viz. the 

 anterior border of the yolk. Nothing, indeed, could better 

 illustrate the features formerly pointed out in regard to the 

 movement of the oil-globule in the gurnard, and the passage 

 of the brightly coloured globule through the yolk (not merely 

 at the surface of the yolk as some imagine) was in this 

 instance easily followed. The free condition of the globule 

 was probably abnormal, but it is noteworthy. 



The larval torsk is characterized by somewhat irregularly 

 scattered chromatophores on the head, though the front view 

 of the head in ovo shows that a more or less symmetrical 

 series is present over each eye. The first patch or bar of 

 finely ramose chromatophores on the trunk is placed rather 

 behind the middle of the yolk, and it is rendered more con- 

 spicuous by the black pigment of the sub-uotochordal region 

 beneath. The next lies on the muscle-plates behind the vent, 

 the last is at the tip of the tail, while a less definite one is 

 intermediate. A slightly yellowish hue (greenish by trans- 

 mitted light) pervades the head, yolk-sac, and the tip of the 

 tail. The rectum is near the upper border of the marginal 

 fin. The notochord is multicolumnar. The reddish oil- 

 globule is situated at the posterior border of the yolk. 



The changes which subsequently occurred may be sum- 

 marized as follows : — increase of the greenish-yellow hue and 

 the ramifications of the black chromatophores, increase of 

 pigment in the eyes, which became greenish silvery, absorp- 

 tion of the yolk, and the gradual diminution of the reddish 

 oil-globule, which has been drawn forward and almost con- 

 cealed under the greatly increased black pigment of the upper 

 region of the abdomen. The appearance of the embryonic 

 rays in the tail was coincident with a more distinct 

 yellowish tint of the marginal fin of that region, and the fan- 

 like expansion of the black pigment of the tail. The larva? 



