SEA-FISHERIES LABORATORY. 283 



than they were in '08, and reach to over 50,000 on 

 November 13th and 16th. Again, Chcetoceros reaches 

 7 figures for the first time on April 27th in '08, and on 

 April 19th and 22nd in '09, and next on May 20th in '08 

 and on May 12th in '09; alter which the numbers fall 

 during the late summer and rise again in autumn. This 

 second maximum was, however, both greater and earlier 

 this year, reaching 875,000 on September 25th, as against 

 70,000 on October 16th, '08. 



Coscinodiscus runs through thousands and tens of 

 thousands in the first three months of both years, and 

 reaches 120,000 on April 13th and 14th, '08, as against 

 65,000 on April 7th, '09. The numbers then rapidly 

 diminish, and reach zero on June 2nd in '08 and on 

 June 1st in '09, and remain low with occasional increases 

 until October, when they become steadier and rise to 

 hundreds, bordering on 1,000, in '08, and to a few 

 thousands (5,500 on December 14th) in '09. 



Rhizosolenia presents a marked contrast to the above 

 species in being practically absent in the first few months 

 of the year, and having its single maximum in June. In 

 '08 it suddenly shows 4,700 on April 13th, and in '09 

 equally suddenly, 5,000 on April 15th; then 40,000 on 

 April 19th, 140,000 on May 12th, 500,000 on June 9th, 

 1,620,000 on June 12th, and the maximum of 2,600,000 on 

 June 15th; '08 has 150,000 on May 20th, 1,137,500 on 

 June 4th, and the maximum of three-and-a-half millions 

 on June 30th. 



Hialassiosira is also absent in the early months of 

 the year, and begins with 2,000 on April 13th in '08, and 

 4,000 on April 15th in '09. Last year the numbers 

 reached 80,000 on May 20th, and ended with 7,500 on 

 June 4th; this year the highest point, 40,000, is on 

 April 19th, 10,000 on May 20th, and 1,000 on May 24th, 



