INTRODUCTION. 



was in reality nothing but those lower aquatic animals which 

 (as is well known) often fill the sea... Gradually these eggs, 

 floating about freely, became more numerous, until, about the 

 end of March, they filled the sea... I now succeeded in following 

 their development step by step until the tender little fish 

 slipped out of the shell and swam about in the water." 



On a calm day on one occasion he found the surface of the 

 sea covered with a dense layer of floating spawn, so that with a 

 sufficiently large net he could have taken tons of it. This 

 occurred over a celebrated fishing-ground, on which the cod 

 were present in enormous numbers, so as to form what the 

 fishermen called a " fish-mountain," the sounding lead or sinker 

 in going down striking them as it passed. He also noticed that 

 the spawning of the cod did not take place all at once, but 

 thought it lasted several days. He also observed that the 

 female fishes were nearer the surface than the males — both 

 eggs and milt rising towards the surface. The haddock was 

 noticed to have similar eggs. In 1866 and 1867 he followed 

 the further growth of the larval cod to the post-larval stage of 

 7 — 8 mm. with their large broad heads and protruding eyes, 

 while their tails vibrated like a fine thread in the surface- 

 water as thej fed on the very minute crustaceans. In June 

 again, in the sounds and inlets inshore, he found a larger stage 

 up to 24 ram. in incredible numbers snapping at the myriads 

 of small crustaceans just mentioned, and which are generally 

 known under the name of herring-food. He failed for 

 some time to get the later stages, but at last he met them 

 and the young haddock sheltering under the discs of the jelly- 

 fishes, for the purpose of feeding on the small crustaceans that 

 are parasitic on them or that become entangled in their 

 envenomed tentacles. His largest form had now reached the 

 length of 40 mm., a little more than 1^ in. Next season he 

 procured in August older forms of 50 to 60 mm., near lines of 

 floating sea-weed and debris, and pointed out how the dark 

 cross-streaks he noticed in the younger forms of the previous 

 year had now dissolved into three or four parallel lines of square 

 spots of a more or less bright reddish-brown colour, which 

 contrasted beautifully with the light hue of the body, resembling, 



