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SEA-FISHERIES LABORATORY. 281 
DISCUSSION OF THE GROUPS. 
We now return to the plankton results, and shall 
consider first the leading groups captured inside the bay. 
Bay Dtatoms 1n 1908. 
The number of Diatoms per haul in Port Wrin Bay 
starts with 6,200 on January 4th, and rises gradually 
through an average of 8,995 in January, 19,625 in 
February, 66,851 in March, to 484,419 in April. There 
is a sudden increase in the middle of April from 64,750 
on April 7th to 329,450 on April 13th, and after that the 
numbers rapidly rise to 1,775,700 on April 29th, to 
2,290,000 on May 20th, and, with falls between, to 
2,873,150 on May 28th, and 2,191,250 on May 30th. The 
numbers keep high during the first week of June, drop 
in the middle of the month, and rise again to over one and 
a half millions at the end (with an exceptional haul 
of over three and a half millions in the coarse net 
on June 30th); after which there is a rapid fall in 
the first half of July leading to a still further reduction 
in August—when Diatoms are practically absent. On 
September 14th the numbers have risen again to 6,800 in 
the fine net, and 2,400 in the coarse net; but the average 
for the month is only 1,415, taking both kinds of net into 
consideration. The numbers are higher for October, 
reaching 149,500 in the fine net, on the 16th, but dropping 
again to 2,700 at the end of the month. On November 
2nd they rise to 6,830 and on November 6th to over 7,700, 
but drop again by the 30th to 1,860, and on December 
4th to 1,230, on December 15th to 210, and on the 23rd 
to 330. The numbers taken in the coarse nets during 
December are much higher, 14,500 on December 4th, 
5,600 on the 15th, 9,030 on the 23rd, and 5,700 on the 
