58 ON DIATOMACEOUS GATHERINGS FROM KERGUELEN's LAND. 



being "02, having a distinct large umbilicus consisting of about eight 

 cuneate areoles, four large and four small. Areoles small, radiate, 

 appearing in the dry valve irregularly quadrate, with an azure pustule 

 in the middle of each. When mounted in balsam, roundish. Of 

 equal size throughout. Closely arranged in fascicles, with about ni 

 or ten rays in each at the margin, but the number decreasing towards 

 the centre. The fascicles have an undulate appearance like the shell 

 of the Pecten. Dry valve iridescent. 



Many fragments of this form were found, some larger, some 

 smaller ; and but a few perfect valves. This form, so large that 

 it would occupy too much space to figure completely, I have plea- 

 sure in naming after the gentleman to whose indefatigable explo- 

 rations we are indebted for the gathering which contained it. 



Actinocyclus Oliveranus. Marine. PI. I. fig. 7. 



Diameter of the valve *0030 ; furnished with a narrow border of fine 

 linear striae, on the inner margin of which the valve is divided by 

 eight equal elliptical undulations deeply shaded, with their crests di- 

 rected towards the centre. Valves areolate ; areoles small, roundish, 

 arranged for some distance concentrically around the inner margin of 

 each alternate undulation, until the lines of areoles reach the margia 

 at the extremity of the next undulation at either side, and thence 

 towards the centre linearly at an angle with the distinctly marked 

 radius which strikes the middle point in the crest of the basal undula- 

 tion. The centre is occupied by a few irregularly arranged areoles. 



This very striking and beautiful form I name after Professor 

 Oliver. 



Actinocyclus Challengeri. Marine. PI. I. fig. 8. 



Diameter of the valve '0028. Furnished with a narrow border with 

 small, close, punctate striae ; remainder of the disk areolate ; areoles 

 small, roundish, radiate, larger in the centre, and decreasing in siz<? 

 towards the margin. 



Neither in this nor in the preceding species w r as there obser- 

 vable a submarginal nodule ; so that with hesitation are they re- 

 ferred to the genus Actinocyclus, to which they otherwise would 

 undoubtedly belong. 



* 



Pixidicula radiata. Marine. PI. I. fig. 9. 



Frustules large ; breadth, on front view, '0028 ; diameter of the valve 

 •0045. The valve is divided into three concentric portions; the cen- 

 tral portion dark brown, unstriate, large, round which there is a Ugh* - 

 fawn-coloured zone, with fine linear striae. Into this zone project 

 longer and shorter dark rays from the central boss, which are alternately 



