MARINE BIOLOGICAL STATION AT PORT ERIN. te 
24th, and 10,970 on the 29th. September begins at a low 
level, reaches 11,942 on the 4th, and, with falls between 
Sereom the I2th,.13,440 and 27,3812 on the 20th, 
mowed oy 10,582 on 21st, 18,450 on 23rd, 11,850 
on 24th, and 12,110 on 80th. October is also high, with 
Mieemowon the Oth, 27,/90 on 14th, and. 24,480 on 24th. 
November shows one high figure, 10,937 on the 8th; 
while December ranges from 1,724 to 2,755; the year’s 
record ending very.much at the same level where it 
commenced in January. The range in number of the 
Copepoda per net, 30 to 29,800, is considerable compared 
with that of some groups, but does not equal that of the 
Diatoms. 
The monthly averages of the Copepoda during this 
year (1907) are as follows :— 
(ieee. «1,816 | July ee a OKO 
iG (SB veya See COE 4 OO, 
Peete a7) |} Sept. ...  ... 6,514 
were 5850 || Oct. | ...- = 17,572 
eo... 3,415 | owen ee ee G.908 
demevs.. ... 12,138) | Dec. OR EO 
The highest averages her (June and October) do not 
quite coincide with the maxima (April an:l September- 
October) as stated above where the days were taken singly. 
The explanation is, of course, that although April contains 
‘a maximum far above that of June, it also contains in the 
earlier part of the month many low records that pull down 
the average when the month is treated as a whole. The 
maxima in high average bulk of catch extending over the 
month, but not in exceptional catches, are seen from this 
list to be in June and October, and especially in the latter. 
If we look now for the largest individual hauls of a 
single species of Copepod we find that they occur in April, 
