22F Canadian Arctic Expedition, 1913-18 
Navicula Lyra Ehr. var. (?) 
Sch. Atlas, Pl. 3, fig. 11. ee : 
The only example of this common species is the very doubtful variety 
above mentioned. Found at Stations 23, 27s, 41 and 43a. 
Navicula maculata Bail. 
Sch. Atlas, Pl. 6, fig. 38, misnamed, and Pl. 244, fig. 2. 
Found at Station 23. 
Navicula maxima Greg. 
Greg. Diat. Clyde, Pl. 9, fig. 18; Sch. Atlas, Pl. 50, figs. 32-33. 
Both the type form and the close variety umbilicata Grun. shown above 
occur, the former at Stations 41 and 48c, and the latter at Stations 41 and 430. 
Navicula oscitans A. Sch., var. (?) 
Sch. Atlas, Pl. 6, fig. 40, unnamed. | 
Cleve considers this a variety of N. oscitans, with which it only partly agrees. 
Found at Station 41. 
Navicula placentula Ehr. 
Van Heurck Syn., Pl. 8, fig. 26. ; 
Recorded as living in brackish water. Found in a plankton haul, Station 
18d. 
Navicula plicata Donk. 
Donk. Brit. Diat., Pl. 9, fig. 2; Sch. Atlas, Pl. 50, fig. 40, no name. 
Found, one specimen, at Station 23. 
Navicula protracta Grun. 
Cl. and Grun. Arct. Diat., Pl. 2, fig. 38. 
Grunow suggests on page 35 above that this may be a variety of N. crucicula 
(W. Sm.) Donk. This is not to be accepted; see Donk. Brit. Diat., Pl. 6, fig. 
14. Found at Station 23s. 
Navicula quadratarea A. Sch. 
Sch. Nordsee Diat., Pl. 2, fig. 26; Sch. Atlas, Pl. 260, figs. 31-38, etc. 
This essentially arctic diatom is unusually variable, many forms being 
represented in the Canadian Arctic Expedition material. Found at Stations 
23, 41, 43a, 43b, 43c, and 48g, also in plankton haul at Station 29g. 
Navicula rhombica Greg. 
Mic. Journ., 1856, Pl. 5, fig. 1; Van Heurck Belgica, Pl. 1, fig. 9. 
What is essentially the same diatom Brun calls Schizonema Japonicum in 
Brun. Espec. Nouv., Pl. 14, fig. 6. Van Heurck’s specimen is from the Antarctic 
and differs considerably from the type. The type form is abundant in the 
Arctic, is markedly so at Stations 20b-c, 20g, 23, 27s, 41, 48a and 43. 
Navicula rhynchocephala Kitz. 
Donk. Brit. Diat., Pl. 6, fig. 4; Van Heurck Syn., Pl. 7, fig. 31; H. L. Sm. 
Types 314. 
This is generally fresh-water, sometimes marine. Found on beach. at 
Bernard harbour, July 15, 1915. The hyaline central area is too large in Van 
Heurck’s figure. 
Navicula rostellata Greg. (not Kitz.) 
Greg. Diat. Clyde, Pl. 9, fig. 20; Sch. Nordsee Diat., Pl. 2, fig. 31, poor. 
Found at Station 20b-c. Near N. apiculata Breb., and so placed by De 
Toni, Syl. Alg., p. 50, and by Grunow in Sch. Atlas, Pl. 46, note. 
