152 MARIE V. LEBOUR. 
(66) Amphiprora maxima Gree. Rare, chiefly in autumn and winter. 
(67) Amphora ostracaria Breb. Rare, only in autumn. 
(68) A. sp. Rare, September and August. 
Genus Nrrzscuta Hassal. 
The species of Nitzschia occur throughout the year and, unless 
entangled in larger organisms, get through the nets in numbers. 
In Pheocystis, Nitzschia species entangle themselves to a large 
extent, chiefly N. closterium and a needle-like species which I 
believe to be N. delicatissima. However, when it is entangled 
it is generally singie or there are two together. It is never in a 
chain or three or five as is often the case with this species when it 
is free. When not entangled it is not so common. 
Fic. 7.—Nitzschia closterium W. Sm. Long and short forms. 3850. 
(69) Nitzschia closterium W. Sm. Occurs throughout the year. Never 
in very large numbers. Two forms are seen (Fig. 7), the long form 
with its ends curled shghtly and a much smaller form with straight 
ends. Possibly the latter is the young just after division. In 
cultures the central part is very often much inflated. At all 
depths. 
(70) N. servata Cleve. Fairly abundant in August and September, rare 
at other times. 
(71) N. delicatissima Cleve. In May and June this species plays an 
important part in the plankton. From July to the middle of 
September it is fairly common, after that occurring only occasion- 
ally. At all depths but largest numbers at 5 and 7 fathoms. 
(72) N. panduriformis Grev. Very rare, September and October. 
(73) Bacillaria paradoxa Gmel. Never in large numbers, but occurs 
throughout the year both in water samples and tow nettings. 
Almost absent in May and early June. 
(74) Campylodiscus sp. At least four species of Campylodiscus occur in 
the tow nettings occasionally. Also Surrirella fastuosa Ehr. 1s 
fairly common. All these are bottom forms and do not strictly 
belong to the plankton. 
