Marine Diatoms 19 F 
t 
Navicula Claviculus Greg. 
Greg. Diat. Clyde, Pl. 9, fig. 5; Sch. Atlas, Pl. 2, fig. 28. 
Found in dredging at Station 41, and plankton haul, Station 12d. 
Navicula Cluthensis Greg. 
Cl. and Grun. Arct. Diat., Pl. 2, fig. 49; Cl. N. and R. Diat., Pl. 2, fig. 13. 
Two varieties represented by the above references; var. finmarchiana 
Grun. found at Station 41, and var. maculifera Cl., at Station 43c. 
Navicula compressicauda A. Sch. 
Sch. Atlas, Pl. 46, fig. 62; Sch. Nordsee Diat., Pl. 2, fig. 35. 
Found at Station 48a. A very rare species. 
Navicula consimilis A. Sch. 
Sch. Nordsee Diat., Pl. 2, fig. 46. 
Strictly typical forms at Station 41c. 
Navicula controversa Mann, nom. nov. 
PL. I, fig. 7. 
Valve panduriform but only slightly constricted at the middle, thus closely 
resembling in outline N. didyma; rows of beading radially arranged throughout, 
becoming arcuate toward the two apices; the beads in each row widely separated 
and appearing to be strung on thread-like lines, two to four beads in each row 
and all near to the outer margin, thereby leaving only the thread-like lines to 
continue to the middle; rhaphe strong, straight, bisecting the wide fusiform 
median area; central nodule rectangular. 
Length 0-079-0-110 mm., width 0-028-0-040; 4-7 to 6 lines in 0-01 mm, 
This is identical with the figure in Cl. and Grun. Arct. Diat., Pl. 3, fig. 54 
there miscalled N. bomboides var. media (see Sch. Atlas, Pl. 13, figs. 36-38) and 
subsequently figured in Grun. Diat. F. Jos. Land, Pl. 1, figs. 38-39, there mis- 
called N. subcincta A. Sch. (see Sch. Atlas, Pl. 13, fig. 41 and Pl. 69, fig. 32). 
It is abundant in some arctic dredgings, especially at Station 43d. I have found 
it also in material of the Shackleton South Polar Expedition, and identical with 
the northern specimens except that it averages larger. 
Navicula cruciata Cl. 
Cl. N. and R. Diat., Pl. 1, fig. 11. 
Cleve’s type form came from Greenland. Found at Station 436. 
Navicula didyma Ehr. 
Sch. Atlas, Pl. 18, fig. 2; Sch. Nordsee Diat., Pl. 1, fig. 7. 
Not at all plentiful; found at Station 43c. 
Navicula directa W. Sm. 
Sch. Atlas, Pl. 47, figs. 3-5; W.Sm. Brit. Diat., Pl. 18, fig. 172. 
Found in dredgings from Stations 20b-c, 23, 41, 43a and 436, and in 
plankton haul at Station 18d, and generally abundant in all. 
Navicula distans (W. Sm.) Ralfs. 
W. Sm. Brit. Diat., Pl. 18, fig. 169. 
Schmidt’s figures of this species in Atlas, Pl. 46, figs. 11-14, are poor. Found 
only at Station 28. 
Navicula elliptica Kitz. 
Sch. Atlas, Pl. 7, figs. 29-32. 
This normally fresh-water species has been reported several times in brack- 
ish dredgings. N. subovalis Cl. in Nav. Diat., I, Pl. 1, fig. 27, is a very similar 
form of truly marine habitat, but having been found only in New Zealand this 
arctic species is probably the above. Found at Station 20g. 
3697—3 
