DIATOMACEiE FROM SPITZBERGEN. 257 



gathering from Jamaica, a fact which shows how indepen- 

 dent these forms are of climatial influences. 



Navicula pinnularia, Cleve, "Oni Svenska och Norska 

 Diatomaceer," ' Ofversigt af Kongl. Vetenskaps-Akad. For- 

 handlingar,' Stockhohn, 1868, p. 224, Taf. iv, figs. 1 and 2. 

 Of this species I found in the gatherings under consideration 

 two well-marked varieties, one just as figured hy Cleve, the 

 other a much narrower form, and with finer striae, which I 

 have given in fig. 4. 



Concerning the forms in the preceding catalogue I have 

 further to remark that Synedra Kamscatica, Grun,, ' Die 

 Osterreichischen Diatomaceen,' p. 404, Tab. viii, fig. 6, is of 

 very frequent occurrence, but the valve, instead of being 

 bowed as Grunow figures it, is invariably straight. It is also 

 much larger, but in all other respects identical. In the 

 middle of the valve, where the striae fail, there is a slight 

 thickening of the margin on either side, and this feature is 

 observable in the r as well as in the s v. (PI. VIII, fig. 5.) 

 This species is at first view liable to be confounded with 

 Synedra tabulata, but it is more slender, the striae very much 

 finer, and the middle of the valve is destitute of striae. 



In addition to the forms included in the foregoing list 

 several species occurred already described, but not included 

 in Cleve's enumeration of Diatoms from the Arctic Sea, viz. : 

 Amphora crassa, Greg. 



„ costata, Greg., not W. Sm. 



„ l(Evis, Greg. 



„ robusta,* Greg. 



„ lyrata, Greg. 



„ proboscidea* Greg. 

 Amphiprora alata* Kiitz. 

 „ costata, O'M. 



Cocconeis arraniensis, Grev. 



„ binotata, Grun. = C. scufiellum, var. Roper. 



„ coronata, Brightw. 



„ distans, Greg. 



„ fimbriata, Ehr. 

 „ major, Greg. 

 „ nitida* Greg. 



„ ornata* Greg. 



„ pseudomarginata,* Greg. 

 „ splendida,* Greg. 

 Coscinodiscus lineatus, Ehr. 



„ radiolatus, Ehr. 



Donkinia compacta, Ralfs. 

 Epithemia constricta, W. Sm. 



