Marine Diatoms 15F 
Denticula tenuis Kiitz. 
Van Heurck Syn., Pl. 49, figs. 23, 28-30. 
_ Although, like the preceding, this fresh-water species occurs in marinega ther- 
ings it probably gets there as detritus washed down from adjacent fresh-water 
areas. Found also at Station 43f. 
Diatoma (DC.) Heib. 
Diatoma tenue (Ag.) Kitz. 
Van Heurck Syn., Pl. 50, figs. 14, 19. 
Found only in plankton haul from Station 21d-f. 
Eunotia Ebr. 
Eunotia praerupta Ehr. var. laticeps Grun. 
Cl. and Grun. Arct. Diat., Pl. 7, fig. 123. 
The specimens exactly duplicate the above figure. Found in dredging 
from Station 23. 
Fragilaria Lyngb. 
Fragilaria islandica Grun. 
Gran Nord. Plankt., p. 114, fig. 153; Van Heurck Syn., Pl. 45, fig. 37. 
Found in plankton hauls from Stations 12b-c, 18d and 460; in the first it is 
very abundant, composing almost the entire plankton. 
Glyphodesmis Grev. 
Glyphodesmis interspiralis Brun. (?) 
Pl. I, fig. 5. See Le Diat., I, Pl. 24, fig. 10. 
By comparing the figure here given with the one in Le Diatomiste the almost 
identical appearance of the two will be seen; but as this species has never before 
been found except in fossil beds at Carmacks and Totara, New Zealand, one 
cannot but question their identity. Of course there are many fossil forms found 
also in a living state, e.g., Navicula Schultzii, but the separation of these two 
geographically, as well as chronologically, is exceptional. A certain specious 
resemblance exists between this diatom and figures of the so-called ‘‘ Homeo- 
cladia Martiana Ag.,’”’ as in Prit. Inf., Pl. 4, fig. 24, and W. Sm. Brit. Diat., 
Pl. 55, fig. 347; but that is a Nitzschia, a quite delicate diatom, well shown in 
H. L. Sm. Types, No. 198. Found only in a dredging from Station 48c, a single 
specimen. 
Gomphonema Ag. 
Gomphonema exiguum Kiitz. 
Van Heurck Syn., Pl. 25, figs. 34-39. 
Found in plankton hauls from Station 43f. 
Gomphonema groenlandicum Ostr. 
Sch. Atlas, Pl. 213, fig. 40. 
Found in two dredgings, from Stations 23 and 43c. 
Goniothecium Ebr. 
oniothecium Odontella Ehr. 
», Ehr. Mikro., Pl. 18, fig. 94; Prit. Infus., Pl. 6, fig. 27. 
‘Generally fossil; found at Station 27s. 
