108 MARVELS OF FISH LIFE 
hundreds of other forms of minute marine life, a few 
perfectly transparent spherical globules, about one- 
twentieth of an inch in diameter. The microscope 
showed these globules to be fish eggs. As the season 
advanced, the number of these eggs in the sea greatly 
increased, and by March they were more abundant than 
any other form of marine life found near the surface 
of the water. So abundant did these eggs become, that 
on a calm day they could be seen from a boat floating 
as a thick layer. 
By the end of May, the sea swarmed with millions 
of transparent little cod, about a third of an inch in 
length. These fish could be seen feeding on the minute 
crustaceans near the surface. By the end of June the 
little cod were about an inch in length, and soon after 
this the majority of them disappeared. Sars again 
found them early in July, sheltering under large jelly 
fish. The young cod, which were now about an inch 
and a half in length, were found to be full of crustacean 
parasites, known as medusa-fleas, similar to those on 
their floating shelters. No doubt young cod gather 
together under the jelly fish in this manner in order to 
obtain this parasitic food, but incidentally this method 
of feeding helps to conceal the young fish from attack. 
Towards the end of July young cod leave the shelter 
of the jelly fish and take up their abode in the seaweed 
amongst the rocks. In a year’s time these fish have 
grown to six or seven inches in length. During their 
second summer the young cod still keep amongst the 
