302 THE COD FAMILY. 



is placed rather behind the middle of the yolk, though a little 

 variation exists, and it is rendered the more conspicuous as the 

 black pigment of the region along the multicolumnar notochord 

 is present beneath. The next patch lies on the muscle-plates 

 behind the vent, the last is at the tip of the tail, while a less 

 definite one is intermediate. Besides the greenish colour (by 

 transmitted light, yellowish by reflected) on the head and tail, 

 the same hue is visible on the yolk-sac. The gut ends towards 

 the upper part of the marginal fin, but a lumen occurs just 

 within the tip. The surface of the yolk-sac, the breast-fins, and 

 the marginal fin, is minutely vesicular. A little black pigment 

 appears in the eye. The larval torsk are healthy and active, 

 and can be transmitted long distances in a limited supply of 

 water. 



The chief feature on the second day was the increase of the 

 greenish-yellow hue on the under surface of the head, on the 

 yolk-sac, and the tip of the tail, from the development of the 

 cutaneous vesicles, formerly mentioned, and such makes a bold 

 contrast with the pinkish oil-globule. The ramifications of 

 the black chromatophores have everywhere increased, those 

 at the tip of the tail presenting a radiate arrangement like fin- 

 rays. The liver appears on the ventral border of the gut, and 

 the termination of the latter has moved a little downwards 

 and often contains a rounded mass. The breast-fins and ear- 

 capsules are larger. 



The changes next day were the projection of the cartilages 

 of the lower jaw, the increase of pigment in the eyes, and the 

 passage of the end of the gut with the urinary vesicle near the 

 fin-margin. The yolk had considerably diminished, and the 

 restless little fishes used the breast-fins in balancing themselves. 

 On the fourth day the eyes showed a greenish silvery lustre, 

 and vermiform movements in the gut were marked, as well as 

 spasmodic jerks of the lower jaw. When the black pigment- 

 corpuscles are placed against a dark background, they appear 

 brownish, as in the cod, rockling and other forms. 



The larvse daily increased in activity, and were characterised 

 by the rapid vibration of the breast-fins. About a week after 

 hatching the mouth had broken through, the yolk was almost 



