SEA-FISHERIES LABORATORY. 317 



The total number of working days is lower, and the 

 total number of species obtained is, in most months, 

 lower. The percentages of Oceanic species (38 to 60*7) 

 show a wider range than in '09, and more of the months 

 show an Oceanic character (5 in '08, 2 in '09). 



The second table for that year for comparison with 

 that of '09 is on p. 315, and shows that: — 



The preponderance of Neritic species in April is 

 chiefly due to Diatoms. For example, Biddulphia aurita 

 and Thalassiosira gravida occur only in this month. 

 Asterionella bleakeleyi, Coscinosira poly chorda, Nitzschia 

 seriata and Rhizosolenia setigera occur only in one other 

 month ; Thalassiosira nordenshioldii and Achnanthes 

 toeniata in two others ; and Ditylium hrightwellii and 

 Chcetoceros sociale in three others. 



Our third available year, '07, treated in the same 

 way, on p. 314, shows the following record: — 



The percentages of Oceanic species range from 40 

 to 57 (being thus intermediate between '08 and '09), and 

 four of the months show an Oceanic character. 



The most noteworthy points in this record are : — 

 (1) the unusual variation in the number of Oceanic 

 species — 10 to 21 ; and (2) the very low percentage of 

 possible occurrences in both Oceanic and Neritic species 

 in September, and of Neritic in August — as shown in 

 Table II for that same year, on p. 316. 



The more Oceanic or more Neritic character of the 

 month in the three years (as determined by the percentage 

 of Oceanic species at the foot of Table I in each case) is 

 seen at a glance in the following table (50 per cent, is 

 represented by a dash) : — 





Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



1907... 

 1908... 

 1909... 



O 

 O 



N 

 O 



N 



N 

 O 



N 



N 

 N 

 N 



N 



N 



N 



N 

 N 



O 



O 



N 

 N 



O 



N 



N 



N 

 N 

 N 



O 



N 



N 





 O 







N. = 







2 



2 



3 



3 



2 







2 



2 



3 



2 







