220 Ernst Østrup. 



Synedra affinis Kütz., var. subtilis Grün., V. H. Syn., Tab. XLI, 

 fig. 18. 



Lo с. Danmarks Havn (Algæ). 



Synedra affinis Kütz., var. tabulata Kütz., Perag. Mar. D. d. Fr., 

 Tab. LXXX, figs. 13-14. 



Lo c. Otr Cape АпкЧ1е (Algæ, 2 sampl.), Koldewey Isl. (Algæ). 



Synedra affinis Kütz. var. tabulata forma carta acuminata. V. 

 H. Trt., Tab. X, fig. 431 (Syn. atf. tabul.). 



Lo c. Otr Cape Amélie (Algæ). 



Among the numerous scarcely discernable varieties of Synedra affinis 

 only the following are recorded from the Arctic Seas, viz. 

 Synedra aff. lancettula: W. Greenl. 



— - parva: W. Greenl., East Arct. S. 



— - talnil. carta acumin.: Greenl., East Arct. S. 



Synedra investiens W. Sm. V. H. Trt., 313, Tab. X, fig. 425. 



Loc. Off Cape Amélie (Algæ, 5 sampl.), Danmarks Havn (Algæ), Kolde- 

 wey Isl. (Algæ). 



Arct. Distr. W. Greenl., East Arct. S. 



Synedra kamtschatica Grun. Øst. Mar. D. Østg., 450, Tab. VII, 

 fig. 85. 



Loc. Off Cape Amélie (Algæ, 3 sampl.), Danmarks Havn (Algæ, 3 sampl.), 

 Koldewey Isl. (Algæ, 3 sampl.), Marg. of the Pack-ice (2 sampl.). 

 Arct. Distr. Greenl., East Arct. S. 

 I have found this species to vary in length from 160 /г to 260 /г. 



Fragilaria Lyngb., 1819. 



Fragilaria Cylindrus Grun. Grun. Fz. Js. Ld., 55, Tab. II, fig. 13. 



Loc. Marg. of the Pack-ice (2 sampl.). 



Arct. Distr. W. Greenl., E. of Greenl., East Arct. S. 



Fragilaria islandica Grun., var. hyperborea Cl., Cl. Vega Exp., 

 484. Tab. nost XIII, fig. 25. 



Long. 66/^. Lat. 7 ju. Str. 11 in 10 /i. 



Valva lineare-lanceolata. Striis media in parte valvæ deficien- 

 tibus, ceterum axin apicalem non attingentibus itaqve aream api- 

 calem magnam relinqventibus. 



Loc. Marg. of the Pack-ice (2 sampl.). 



Arct. Distr. According to Cleve: "Greenl., Bessels Bay." 



This species must undoubtedly be Cleve's Frag. isl. hyp. about which 

 he says (1. с): "Area longer, striæ 12 in 0,01mm.'" 



Fragilaria striatula Lyngb. V. H. Trt., 324, Tab. XXX, fig. 841. 



Loc. Koldewey Isl. (3 sampl.). 



Arct. Distr. W. Greenl., East Arct. S. 



Plagiograrama Grev., 1859. 

 Plagiogramma Gregorianum. Grev. , V. H. Trt. , 338, Tab. X, 

 fig. 390. 



