346 DISCOVERY REPORTS 



Connective zone simple. Chromatophores : several small plates. Apical axis of cell 

 130-160/x ; transapical axis 40-45/x. 

 Observed at St. WS481. 



Genus Trachyneis Cleve 



Cleve, 1894 



Trachyneis aspera (Ehrenberg) Cleve. (PI. X, fig. 10.) 



Cleve, 1894, p. 191. 



Navicula aspera (Ehrenberg) Donkin, 1871-3, p. 62. 



Cells usually solitary. Valves laminate, weakly elliptic to linear-lanceolate. Apices 

 rounded. Raphe very distinct, surrounded by a narrow axial area, sometimes having the 

 appearance of being weakly sigmoid. Central area dilated to form a stauros which be- 

 comes wider as it moves towards the valve margin, but terminates short of the margin, 

 not joining it. Valve surface furnished with bold striae which are slightly radiate 

 throughout. Connective zone simple. Apical axis of cell 180-220/M ; transapical axis 40/x. 



Observed at St. WS481. 



Scoresbya Hendey, gen.nov. 



Frustula libera, rarissime subseriato-coalescentia ; valvae lanceolatae vel lanceolato- 

 lineares, exacte symmetricae, nodulis centrali terminalibusque donatae; superficies 

 striata, striae moniliformes partem mediam occupantes, segmentis marginalibus exceptis. 



This genus is named after the R.R.S. 'William Scoresby' in which the operations in 

 the Bransfield Strait were carried out during 1929. 



Scoresbya Kempii Hendey, spec.nov. (PI. IX, figs. 16, 17.) 



Valvis lineari-ellipticis, apicibus acutis; raphe conspicua, margine prominente; 

 nodulo centrali distincto, lentiformi ; nodulis terminalibus minutissimis ; striis transversis, 

 moniliformibus, parallelis, subtilissimis, stauro parvo excepto. 



Mensura valvarum 240 x 30/u,. 



Hab. in aquis marinis "Bransfield Strait" prope insulam "Astrolabe" dictam, in 

 mari Antarctica. 



Typus in Herb. Mus. Brit. No. 33965. 



This species is named in honour of Dr Stanley Kemp, F.R.S., until lately Director 

 of Research to the Discovery Committee. 



This species was extremely rare. Seven specimens only were found after much search- 

 ing. The structure of the cell was most characteristic and from the examination of the 

 few specimens available, it is likely that the transverse section of the cell would present 

 a rectangular appearance, the opposing raphes occupying angular positions. In the first 

 instance I was tempted to place the species in the genus Navicula but soon became aware 

 that none of the subgeneric groups of either Cleve or Van Heurck would accommodate 

 it. The relatively large hyaline areas along the margins of the valves, which are separated 

 from the central striate portion by a line, present some entirely new characters in the 



