120 BULLETIN OF THE BUREAU OF FISHERIES 
some years and entirely absent in others. In all areas investigated it forms its 
greatest maxima in the spring. In the spring of 1923 it reached its maximum in 
January, remaining throughout March. The following winter it arrived slightly 
earlier and increased rapidly, swarming early in November (figs. 10 and 11, p. 105). 
Throughout the winter season it remained as the most dominant species. 
The distribution of diatoms during the past year may have been unusual. 
Certainly two seasons’ changes are not sufficient from which to draw conclusions. 
However, as all available records for past years seem to indicate similar summer and 
winter maxima, it is probable that yearly variations will be in the date of the 
appearance of these same species and not so much in the species themselves. Winds 
May carry in unusual oceanic species, but these may be considered accidental visi- 
tors whose appearance again can not be predicted. The following diatoms appeared 
in surface collections of the past year: 
Actinoptychus undulatus (Bailey). 
Asterionella japonica, Cleve. 
Bacteriastrum varians, Lauder. 
Bellerochea malleus (Brightwell). 
Biddulphia alterans (Bailey). 
B. biddulphiana (Smith). 
B. favus (Ehrenberg). 
B. granulata, Roper. 
B. rhombus (Ehrenberg). 
B. vesiculosa (Agardh). 
Cerataulina bergonii, Peragallo. 
Cheetoceros atlanticum, Cleve. 
. boreale, Schiitt. 
. cinctum, Gran. 
. coarctatum, Lauder. 
. contortum, Schiitt. 
. criophilum, Castracane. 
. danicum, Cleve. 
debile, Cleve. 
. decipiens, Cleve. 
densum, Cleve. 
diadema (Ehrenberg). 
didymum, Ehrenberg. 
. laciniosum, Schiitt. 
lorenzianum, Grunow. 
. mitra (Bailey). 
peruvianum, Brightwell. 
. schiittii, Cleve. 
. sociale, Lauder. 
. teres, Cleve. 
. willei, Gran. 
Corethron valdivie, Karsten. 
Cyclophora tenuis, Castracane. 
Ditylium brightwelli (West). 
Fragilaria crotonensis (M. Hd- 
wards). 
Grammatophora marina, Kiitz- 
ing. 
aeaaaneaaqaanaaaaaaaaaa 
G. serpentina, Ehrenberg. 
Guinardia flaccida (Castracane). 
Hyalodiscus stelliger, Bailey. 
Leptocylindrus danicus, Cleve. 
Liemophora flavellata, Smith. 
L. lyngbyei (Kiitzing). 
Melosira borreri, Greville. 
Nitzschia closterium, Smith. 
N. longissima (Brebisson). 
N. paradoxa, Grunow. 
N. seriata, Cleve. 
Paralia suleata (Ehrenberg). 
Rhabdonema adriaticum, Kiitzing. 
Rhizosolenia alata f. genuina 
(Gran). 
R. alata f. gracillima (Cleve). 
R. calear avis, Schultze. 
R. delicatula, Cleve. 
R. feerceensis, Ostenfeld. 
R. hebetata var. semispina 
(Hensen). 
R. setigera, Brightwell. 
R. shrubsolei, Cleve. 
R. styliformis, Brightwell. 
Skeletonema costatum (Gre- 
ville). 
Stephanopyxis appendiculatus, 
Ehrenberg. 
Striatella unipunctata (Lyngbye). 
Synedra gallionii, Ehrenberg. 
S. undulata (Bailey). 
Thalassiosira decipiens (Grunow). 
T. hyalina (Grunow). 
T. nordenskidldii, Cleve. 
Thalassiothrix frauenfeldii (Gru- 
now). 
T. longissima, Cleve and Grunow. 
T. nitzschioides, Grunow. 
