SEA-FISHERIES LABORATORY. 155 
of phyto- and zoo- plankton, and does not contain the 
large Calanoid Copepoda in any quantity. A haul taken 
off the Cock of Arran at the same season in the previous 
year, from a depth of 80 fathoms, had a fair number of 
large Copepoda, mixed however with Diatoms 
(Rhizosolenia semispina, Chaetoceras boreale, &c.), 
Peridinians and some smaller Copepoda. Another haul 
in the same spot in 1907 is of the same nature, with a 
still larger proportion of the smaller Copepoda (mainly 
Pseudocalanus elongatus and Oithona similis) and their 
nauplii. One in the Sound of Bute from a depth of 95 
fathoms, on July 30th, 1908, had, along with the 
Calanoids and some smaller Copepoda, a very large 
number of Diatoms (chiefly species of Rhizosolenia), so 
much so as to be almost a phyto-plankton in appearance. 
Two hauls taken south of Holy Island, Arran, from 54 
fathoms, in 1908, show also a mixed plankton, consisting 
of Diatoms and Peridinians along with the Copepoda. 
A haul from 80 fathoms in Kilbrennan Sound, on the 
West of Arran, on July 26th, 1907, consists of a coarse 
zoo-plankton, in which however there are many small 
Copepoda (Pseudocalanus and Orthona), and other 
animals (Oikopleura and larval forms), and a few 
Peridinians and Diatoms (/thizosolenia semispina) mixed 
with the large Calanoid Copepods. 
There are four vertical hauls taken, one in 1909 and 
three in 1910, off Ardmore, North of Mull, in the 
centre of the channel between Mull and Ardnamurchan 
(for full details see p. 149). These, and a vertical haul 
taken in the neighbouring Loch Sunart in 1910, are all 
alike in general character, consisting of a fine greenish 
phyto-plankton mixed with some Copepoda and nauplii 
and a few Orkopleura. The Diatoms are, in all the cases, 
mostly species of Chaetoceras. In 1910 there were also 
