SEA-FISHERIES LABORATORY. ZT 
May. As the Diatoms are well represented this year, 
we think it worth while to print our records of these 
seven genera in full, in place of summarising the results 
as we did last year. The lst that follows can be 
compared with the similar list for the five genera, 
Biddulphia, Chaetoceras, Coscinodiscus, Rhizosolenia 
and Thalassiosira, given in our Part II, for the year 
1908, and with the remarks at p. 220 in Part III, for 
1909. 
Biddulphia.—Beyond being more abundant this 
year, B. mobiliensts shows no marked difference from 
the previous records. It has its chief maximum (half a 
million) in the middle of April, and a secondary one in 
early winter (61,000 on October 31st and 93,000 on 
December 5th). 
Chaetoceras.—This is the most abundant form in 
the spring phyto-plankton, and this year it reaches the 
very high figure of nearly 49 millions in one haul on 
April 22nd. Its course through the rest of the year 
agrees with that of previous years, having a minimum in 
August and a second maximum in autumn, reaching 
nearly three millions per haul late in September and 
over one million on several occasions in October. 
_Coscinodiscus.—Here again, beyond showing higher 
numbers than on former occasions, there is nothing 
noteworthy. 
Rhizosolenia.—Again, this genus is feebly repre- 
sented until April, and has its maximum in June 
(13 millions on June 14th). It is absent during most of 
August, and has a somewhat sporadic secondary 
maximum in September and October (470,500 on 
September 26th). 
Thalassiosira.—This is somewhat like Rhizosolenia, 
but is less abundant and has its spring maximum earlier 
