SEA-FISHERIES LABORATORY. 139 
information, not merely as to the larger organisms of the 
zoo-plankton, but as to the planktonic conditions in 
general in both surface and deeper water along the 
North coast of Ireland and off the West of Scotland. 
With the view of making a preliminary contribution 
to such knowledge as is required, one of us has spent a 
few weeks (July) during the last four summers (1907- 
1910, inclusive) in taking plankton hauls from the 
S.Y. “‘ Ladybird’”’ at various localities off the West 
Coast of Scotland; while the next few weeks (August and 
September) in each year were occupied in similar work 
further South in the Irish Sea. Even a_ superficial 
comparison of the two series of collections formed shows 
that the state of affairs in the Hebrides is very different 
from that in the Irish Sea, and is evidently worthy of 
more detailed examination and of careful consideration.* 
The plankton hauls from the yacht were in all cases 
taken with the same nets and by the same method, so 
that the various gatherings are as nearly comparable as 
is possible. All the vertical hauls were made with the 
smaller ‘‘ Nansen’’ closing-net (fig. 3) of No. 20 silk, 
and having a mouth of 35 cm. in diameter. Surface 
gatherings were sometimes taken at the same time with 
ordinary open surface tow-nets ‘made of the same silk 
(No. 20) as the ‘‘ Nansen ’’ net and of approximately the 
same size of mouth. The Lucas sounding machine 
(fig. 4), fitted with 200 fathoms of pianoforte wire, was 
found to be most convenient and expeditious in taking 
these deep vertical hauls. 
The temperature of the surface water of the sea in 
the Hebrides varied in this last summer, during the 
month, from 11°8°C. on July llth, off Canna, to 
131°C. on July 19th, off the North point of Eigg. 
* A preliminary account of this work was laid before the Linnean 
Society on Noy. 3rd, 1910,’and published in Linn. Soc. Journ., 
Zool., vol. xxxii, No. 208. 
