SYSTEMATIC ACCOUNT 341 



Subfamily COCCONEIOIDEAE 



Genus Cocconeis Ehrenberg 

 Ehrenberg, 1838 



Cocconeis antiqua Tempere et Brun. 



Tempere and Brun, 1889 (1890), p. 32, pi. 8, fig. 5. 

 Cleve, 1895, p. 177. 



Cells oval, small, with dissimilar valves. The upper valve has a stout margin, fur- 

 nished with short radiating lines of puncta ; lines varying in length, being composed of 

 from four to ten granules in each line. The central area of the valve surface is covered 

 with puncta somewhat irregularly arranged and is divided by a narrow, fusiform, and 

 almost plain area arranged in the apical axis. The puncta of the central area are separated 

 from those of the marginal lines by a hyaline space. The lower valve bears a narrow 

 hyaline band immediately inside the margin surrounding the broad central area, which 

 is covered with curved moniliform striae arranged on either side of the raphe. Hyaline 

 central area narrow. Apical axis of cell 60-76/u, ; transapical axis 42-54/*. 



Observed at Sts. WS 481 ; MS 100, 101, 102, 103. 



Cocconeis ceticola Nelson ex Bennett. 



Bennett, 1920, vol. xci, p. 355. 

 Hart, 1935, p. 256, pi. 11, figs. 1-4. 



Cells solitary, that is, not united to form chains, but found often forming large 

 colonies. The outline of the valves is elliptic-lanceolate, the apical axis of the cell being 

 about twice as much as the diameter. The cells are strongly concavo-convex. The upper 

 valve possesses a straight pseudoraphe which is dilated very slightly in the median area 

 of the valve, forming a small lanceolate hyaline area. Valve surface covered with sub- 

 radiate striae; margin strongly punctate. The lower valve possesses a strong raphe, 

 somewhat sigmoid. Raphe surrounded by a narrow axial area which dilates towards the 

 centre of the valve to form an oblique stauros which tapers to a fine point as it ap- 

 proaches the valve margin. Valve surface covered with extremely fine striae; margin 

 strongly punctate. One of the most characteristic Antarctic diatoms, and the peculiar 

 structure of the stauros upon the raphe-bearing valve is unique in the genus Cocconeis. 

 Apical axis of cell 22-3 2/x ; transapical axis 12-20/^.. Type locality : in the skins of Balaen- 

 optera musculus and B. physalns, South Shetlands. 



Hart (1935) has dealt fully with the distribution of this organism in his highly suc- 

 cessful account of its occurrence in the cutaneous investment of certain cetaceans, par- 

 ticularly the Blue and Fin whales, Balaenoptera musculus and Balaetioptera physalus, and 

 more rarely upon the Sei and Sperm whales, Balaenoptera borealis and Physeter catodon. 

 He was able to show that the infection takes place during the southerly feeding migra- 

 tion and that the strong development of the schooling habit is responsible for its 

 appearance amongst certain classes of whales. Hart was able to show also that the 

 thickness of the diatom film indicated in a rough manner the length of time the whales 



