i68 DISCOVERY REPORTS 



Family ACHNANTHACEAE, West, 1927 

 Genus Achnanthes, Bory, 1822 

 Achnanthes spp. 



Observed at a very few inshore stations and on pack-ice. 



Genus Cocconeis, Ehrenberg, 1838 

 Cocconeis costatum, Greg. 



Gregory, 1855, p. 39. 



A small form probably referable to this inshore species was observed at one inshore 

 station in Bransfield Strait. 



Family NAVICULACEAE, West, 1927 



Genus Navicula, Bory, 1822 

 Navicula oceanica, Karst. 



Karsten, 1905, p. 126, pi. xviii, fig. 4. 



Present in moderate numbers at seven stations round South Georgia during the 

 spring survey, and at a few other stations, all in comparatively old Antarctic surface 

 water, in the Bellingshausen Sea. 

 Navicula pellucida, Karst. 



Karsten, 1905, p. 126, pi. xviii, fig. 12. 



More numerous than the last named round South Georgia in spring and present in 

 moderate numbers at a few stations farther south in both the Weddell and Bellings- 

 hausen Seas. 

 Navicula spp. 



Small indeterminate members of this genus occurred with some frequency in small 

 numbers, especially close up to the ice-edge. 



Genus Tropodoneis, Cleve 

 Tropodoneis antarctica (Grun.), Cleve. 

 Karsten, 1905, p. 128, pi. xviii, fig. 7. 

 At one station only, on the spring survey round South Georgia. 



Genus Amphora, Ehrenberg, 1840 

 Amphora spp. 



Observed on one or two occasions in the vicinity of pack-ice. 



Genus Cymbella, Agardh, 1822 

 Cymbella spp. 



Observed on pack-ice and rarely in the plankton in close proximity to pack-ice. One 

 species occurs constantly on the baleen of southern rorquals at South Georgia. 



