246 THK JOURNAL OF BOTANY 
Geyser, temp. 40° C. Many of the specimens were large and 
pone with the markings reaching almost up to the median 
lin 
"36. Navicula borealis (Ehrenb.) Kiitz. Hveravellir, temp. 55° C. 
In from the Great Geyser, temp. 40° C. 
96. Navicula Brébissonit Kiitz. Hveravellir, temp. 24° and 49° C. 
Navicula gibba (Fuhrenb.) Kutz. Hyveravellir, temp. 55° C. 
Kerlingarféll, temp. between 80° and 50° 
98. Navicula oblonga Kiitz. Hveravellir, temp. 61° C. 
29. Navicula oculata Bréb. Hveravellir, temp. 55° 
ns Navicula mutica Kiitz. var. quinquenodis. Hyerivellia: temp. 
55° C. 
pe > a Navicula subcapitata Greg. Hveravellir, temp. 88° and 
82. — rhomboides (Ehrenb.) Bréb. Hveravellir, temp. 
49° and 5 
Var. saxonica (Rabenh.) West & G. 5. West. Hveravellir, = 
Ses of 24°, 88°, 49°, and 55° C. This species was 1} 
3. Gomphonema Aye ar Ehrenb. Hveravellir, temp. 
also at a dataparstat e of 49° C. with sporangial valves. ‘Seale 
from the Great Geyser, gee 40° 
er Achnanthes microcephala (Kiitz.) Grun. Hveravellir, temp. 
85. Achnanthes linearis (W. Sm.) Grun. Kerlingarfoll, temp. 
between 30° and 50°. 
“ie on Achnanthes lanceolata (Bréb.) Grun. Hyveravellir, temp. 
87. Achnanthes Hungarica Grun. Kerlingarfoll, temp. between 
30° and 50° C. 
88. Epithemia turgida (Ehrenb.) oor Hveravellir, temp- 
88° C.; in spray of small geyser, temp. 85° C. 
9. Epithemia gibba Kiitz. var. ventricosa (Kutz z.) Van Heur ck. 
Hveravellir, at temperatures of 24°, 49°, 55° (very ovat valves, in 
many cases no longer than broad), and 61° C. In spray of 8 mal 
ithemia Argus (Khrenb.) Kiitz. she or less abundant 
in ne same uiaicns s as the preceding specie 
. Epithemia gibberula (Ehrenb.) Kitz. “With the preceding 
species, but not so abundant. 
42. Eunotia Arcus Ehrenb. ae short, stout forms; 
very abundant at a temperature from O°-C. 
48. Eunotia exigua (Bréb.) Rabenh. as ve preceding species. 
44, Synedra Ulna cae oor ath var. lanceolata (Kiita tz.) Van 
Heurck. Hveravellir, tem 
45. sores fico ite Kiitz. Kerlingarfoll, temp- 
between 30° a 
