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TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY 



The first fertilised eggs of the plaice were found in 

 the pond on March 3rd, and the numbers increased day by 

 day until April 12th, when fully 500,000 were collected. 

 After that date the numbers began to diminish, and none 

 were collected after May 5th. 



The method of estimating the number of eggs by 

 measuring the bulk in a graduated cylinder, as followed 

 hitherto and elsewhere, was found to be very destructive ; 

 so after a trial, extending over a fortnight, it was replaced 

 by the method of counting measured samples. The 

 numbers of eggs collected during the first fortnight, and 

 estimated bv the former method, were as follows: — 



Date. 

 March 10th 

 „ 12th 



14th 



15th 



16th 



17th 



18th 



19th 



21st 



22nd 



23rd 



24th 



25th 



26th 



28th 



29th (stormy day; 



31st ... ... 



Number of Eggs 



. . 10,000 



. . 10,000 



.. 40,000 



.. 25,000 



.. 50,000 



.. 100,000 



.. 18,000 



. . 24,000 



.. 2,500 

 9,000 



.. 11,000 



.. 16,000 



.. 15,000 



.. 12,000 



.. 30,000 



.. 2,000 



. . 30,000 



After the last date the amount of eggs was estimated 

 by counting the actual number in samples containing 

 10 e.c. of water taken three or four times from the 



