Marine Diatoms 13 F 
Coscinodiscus curvatulus Grun. 
Sch. Atlas, Pl. 57, fig. 30; Grun. Diat. F. Jos. Land, Pl. 4, figs. 9, 11-14. 
At two stations, Nos. 41 and 439. 
Coscinodiscus decrescens Grun. var. repleta Grun. 
Grun. Diat. F. Jos. Land, Pl. 3, fig. 18. 
Judging from Grunow’s figure this is too wide from the normal form to be 
a good variety. Found in dredgings at Station 23. 
Coscinodiscus excentricus Ehr. 
Sch. Atlas, Pl. 58, figs. 46-49, the last the type form. 
Widely distributed in the Arctic, in fact cosmopolitan. Found in dredgings 
at Stations 43a and 43g, and a plankton haul from Station 25b-c, all in con- 
siderable abundance. 
‘Coscinodiscus heteroporus Ehr., var. (?) 
Sch. Atlas, Pl. 61, fig. 4. 
A species of doubtful worth. Found in a plankton haul at Station 43/. 
Coscinodiscus kryophilus Grun. 
Grun. Diat. F. Jos. Land, Pl. 3, fig. 21. 
In only one dredging and there infrequent, Station 29g. 
Coscinodiscus Kiitzingii A. Sch. 
Sch. Atlas, Pl. 57, figs. 17-18; Sch. Nordsee Diat., Pl. 3, fig. 35, misnamed. 
Found only in dredging made at Station 43a. 
Coscinodiscus limbatus (Ehr.) A. Sch. 
Sch. Atlas, Pl. 65, fig. 7; Ehr. Mikro., Pl. 20, fig. 29. 
There is confusion about this species. Grunow would unite it with C. 
radiatus Ehr., and De Toni puts it under C. marginatus Ehr. See discussion in 
Schmidt above. Found only at Station 29g. 
Coscinodiscus lineatus Ehr. . 
Sch. Atlas, Pl. 59, figs. 27-30; Van Heurck Syn., Pl. 131, fig. 3. Found 
sparingly at Stations 43a and 48b, and the doubtful variety called C. blandus 
A. Sch. in his Atlas, Pl. 59, figs. 35-37, at Station 41. I have specimens of this 
diatom from the Gulf of Mexico in which one valve is like Schmidt’s figures 
and the other exactly like C. lineatus. 
Coscinodiscus marginatus Ehr. 
Sch. Atlas, Pl. 62, figs. 1-6. 
Greville’s C. robustus, generally united with this species, proves to be a 
wholly different diatom, an Endictya. Found in dredging at Station 23, and in 
a plankton haul, Station 43f. 
Coscinodiscus nitidus Greg. 
Sch. Atlas, Pl. 58, figs. 17-19. 
One broken specimen at Station 23. 
Coscinodiscus nobilis Grun. 
Jour. Roy. Mic. Soc., 1879, Pl. 21, fig. 1; Jan. Gaz. Exp., Pl. 6, fig. 13. 
The figure by Janisch above is the only good one of this large and delicately 
marked diatom. Found at Station 20b-c; so far as I know not found previously 
north of England. The locality of the Gazelle specimen is not given. 
Coscinodiscus Oculus-Iridis Ehr. 
Sch. Atlas, Pl. 60, fig. 13. 
The specimens were close to C. pacificus Ratt., but as Grunow suggests 
(Denk. Wien. Akad., 1884, p. 77) this should be classified C. Oculus-Iridis, var. 
pacificus. Found at Stations 23 and 29g. 
