SEA-FISHERIES LABORATORY. 83 



and Witch eggs were fertilized, and underwent partial 

 development, but died after three days. 



Development in the Plaice eggs proceeded through its 

 usual course with scarcely any mortality, and at the end of 

 twelve days, the hatching of the larvae commenced, and was 

 completed on the following day. Shortly after hatching 

 was completed the larvae were carefully transferred to 

 glass aquaria, through which a constant circulation of 

 water was maintained, and when they were a week old 

 various experiments were tried to persuade the larvae to 

 feed. To one jar material collected in the filter was 

 added ; to a second, Diatoms ; to a third, Copepoda ; to a 

 fourth, plankton from the tow-nets, and to a fifth, " Mussel 

 broth " obtained by squeezing up the living shell-fish and 

 passing the semi-fluid mass through a fine sieve. All 

 these experiments were of no avail, and the larvae began 

 to die of! when they reached the age of fourteen days. 

 During the following fourteen days there was a consider- 

 able daily mortality, and at the end of twenty-nine days 

 all the larvae were dead, they, apparently, having made no 

 attempt to feed, as no trace of food could be seen in the 

 stomach when examined under the microscope. 



Other expeditions were made to our own spawning 

 grounds in search of mature fish, but no more fish eggs 

 could be obtained. 



The method of collecting fertilized eggs by the steamer 

 is one of some difficulty and uncertainty, owing to the 

 stormy weather sometimes experienced during the spring 

 of the year. It may happen that just at the very time 

 spawning fish are on the ground it is unsafe for the 

 steamer to venture out. The collecting of eggs from fish 

 caught in the net of an ordinary trawler is also unsatis- 

 factory, owing to the circumstance that when the eggs are 

 ready for shedding the least pressure on the sides of the 



