Diatoms from North-East Greenland. 215 



tissimo."' As to the present specimens the matter stands as follows: — On all 

 my specimens I have seen a median apical line (a "raphe" or an "apical 

 area"), on some specimens I have observed the terminal nodules a little 

 remote from the apices. On a few specimens I think I have seen a trace 

 of a central nodule, but I am not quite sure of it and therefore I have not 

 put a central nodule in my figures. On the other hand I have been able in 

 some specimens to see a striation at right-angles to the apical axis. A speci- 

 men in zone-view, which I had the good fortune to observe showed the 

 frustule bent along the transapical axis after the manner of an Achnanthes, 

 but I have not been able to see the frustules united into a band, on the 

 contrary I think I observed them attached separately to the narrow branches 

 of other x\lgæ after the manner of a Cocconeis. 



Achnanthes rhombica sp. nova. Tab. nost. XIII, fig. 18. 



Long. 34 u. Lat. 12«. Str. 11 in 10«, iitrisqve in valvis, trans- 

 verse lineatis. 



Valva elongale-rhombica. Epitheca: Striis parallelis, area apicali 

 distincta. 



Hypotheca: Striis valde radiantibus, mediis aliqvantum spatiatis. 



Raphe area hyalina, media in parte valvæ in aream conspicuam 

 rotundatam dilatata, cincta. 



Loc. Off Cape Amelie (Algæ). 



The epitheca of this species resembles that of Ach. Lorenziana Grun., 

 but is somewhat more closely striated. As I have seen both valves in situ 

 I am quite certain that the present species cannot be Achn. Lorenz, in which 

 the number of striæ on the hypotheca is stated to be 18—27 in 10 ß (cf. Cl. 

 Syn., II, 187). 



Achnanthes septentrionalis sp. nov. Tab. nost. XIII, fig. 21. 



Long. 19/i. Lat. 9//. Str. 11 in 10« utrisqve in valvis, transverse 

 lineatis. 



Valva lanceolata, apicibus subrostratis. Epitheca: Striis paral- 

 lellis, area apicali distincta. Hypotheca: Striis radiantibus, media 

 in parte valvæ aliqvantum spatiatis. Raphe area hyalina, media 

 in valva in aream rotundatam dilatata, cincta. 



Loc. Off Cape Amélie (Algæ). 



Achnanthes septentrionalis var. subcapitata var. nova. Tab. 

 nost. XIII, fig. 22. 



This variety agrees entirely with the main species in the dimensions 

 and the number of striæ, but differs in the subcapitate apices and in the 

 absence of a central area on the hypotheca. 



Loc. Off Cape Amélie (Algæ). 



Achn. sept, is probably most nearly allied to Achn. Hauckiana Grun. 

 (V. H. Syn., Tab. XXVII, figs^ 14-15). 



Subg. Achnanthidium (Kütz., 1844) Heib.. 1864, CI., 1895 pro. gen. 

 Achnanthes brevipes Ag. var. typica, CI. Syn., II, 193; V. H. Trt., 

 Tab. VIII, fig. 324. 



