SEA-FISHERIES LABORATORY. Lil 
ARRAN, SOUND OF BUTE, ETC. 
July 26, ’07 76-80 1 Z. O. 
a PENS 76 1 Z. O. 
sso COFEUS 95 1 Z. 20. Diatoms also present. 
(mixed) 
enous UO 80 1 Z. O.-N. A few Diatoms. 
ol O8 54 2 Z. 20; A few Diatoms and Peridi- 
(mixed) nians. 
Aug. 1,710 70 1 Pp — Copepoda, etc., present also. 



IrnrsH SEA—MIpD-CHANNRL. 



Date. Depth in No. of Zoo- or Remarks. 
Fathoms. Hauls. Phyto- 
Plankton 
Apr. 7, 09 60 40 B, ) Typical Spring Neritic 
eo. Uo 60 5 IR ) Phyto-plankton. 
Aug. 6,709 59 to 60 5 Z. 
$5 , 09, 60 to 70 4 Z. |" 
» 10,709 60 to 73 4 Z. (mixed) 
» 17,708 . 60 to 70 6 Z (mixed). -A few Diatoms present. 
ee Ug 60 10 Z. (mixed) 
Sept. 4, 07 60 12 ze 
Seles OF 60 6 Z. (mixed) ) Diatoms getting more 
» 12,708 60 and 70 2 Z (mixed) ] 
) numerous. 

Thus we have evidence that off the North-West 
coast of Scotland, at one time of year (July) in several 
successive seasons, the plankton, as sampled by vertical 
hauls, was of different types (zoo- or phyto-plankton and 
neritic or oceanic) in different localities, but preserved 
a fairly constant character in each. 
Now in the Irish Sea, around the Isle of Man, as we 
have shown in the earlier parts of this paper, when the 
plankton of the whole year is considered, it is clear that 
neighbouring localities do not present widely different 
characters as they do in the Hebrides, and that a zoo- 
plankton and a phyto-plankton do not occur simul- 
taneously a few miles apart. 
In the Hebrides, as we have seen, very large 
phyto-plankton hauls may be taken year after year in 
July—when in the Irish Sea the hauls are for the most 
