[197,08 0g 
NAN 
NN 
135 
SEA-FISHERIES LABORATORY. 
(although occasional hauls of some Diatom, such as 
Rhizosolenia, may be large), and is sometimes scarcely 
apparent. Both are caused by a very marked increase 
in the phyto-plankton, chiefly Diatoms (see lists in 
Table, p. 174); and the species which are the most 
abundant and characteristic at the two seasons are, for 
the most part, distinct.* 
07 
°o 
N 
o7 
98,09 
Cf4 
644 
07,0809 
2S GR ES Se Se eS eS 
ne Es eS ee ee 
SC RS SSE EE Se aE 
OR ,09 
oo 
REY: BO 
ARKAARKARARYN 
SSSESSSESSN 
08 ,O9 
07 08.0 8 
° 
=) 
3 Oh TAS 
08.09 
07,08, 09 
=.) eS SE SS TS 
By kWh SRS BS ae ee 
07,09 09 
08,09 
eae ae ae 
| A eee ae | 
eae eee SS 
08.09 3 
WITT LET oe 
eee SSS Se ee 
ASAD AVATAR BAS BS 
ROCQUNreee 
NYSE RAINS 
IIS RAINY 
KKSAAANAASN I 
Shore 
ERM 
Sy 
IAS R ORES SAMY RR ESBEES EEE WI SSS Sass 
BSGRRaeaBeele 
TIT EEREREISYTT ES SSS SSS SOY 
NOR ININISESNING DS RSRINININING NS SOR. ONS SU Nk eee 
YR hb bS. 4’ ee _ Si a] =e ee 
o 
wm 9 oS 
NJ 
SN 
é 
Moy Sd 
In summer, when the phyto-plankton is practically 
absent, the zoo-plankton reaches its maximum; but, in 
bulk, even at the maximum, the zoo-plankton (except on 
rare occasions when there is a swarm of some Copepod 
such as Calanus) is small compared with the spring 
gatherings of phyto-plankton (see columns D and E£). 
A phyto-plankton gathering in the Irish Sea is 
* See Trans. Biol. Soc. Liverpool, vol. xxii, p. 202, 1908. 
