7i 



Diam. of valve, 0*133 m - m - 



I Ham. of area to termination of rays after their interruption, 

 o'o665 m in. 



Diam. of central smooth space (Raphe), 0*0065 m.m. 



Length of marginal beads (Rays), 0*006 m.m. 



Breadth of the interruptions of the rays, o*oio m.m. 



Length of the portion of the beads after the interruption, 

 0-005 ni.m. 



Breadth of the smooth space between apex of rays and striae, 

 00 1 6 m.m. 



Length of short lines bordering Raphae, 0*0065 m.m. 



Valves circular. Rays short, linear, starting from a small, 

 basal granule on the margin of the valves. Inter-radials forming 

 a conspicuous row of regularly oval beads. This row of beads is 

 followed by a blank space which runs all round the valve. After 

 this blank space the continuation of the Rays form a second 

 concentric row of smaller beads. After this row of smaller beads 

 comes a crescentic, smooth space, limited internally by a series of 

 parallel, linear granules, which limit the median clear space or 

 Raphe. Marginal beads about 80 in number. Linear granules of 

 centre about 30 on each side of Raphe. All the smooth regions 

 of the valves appear to be without any trace of punctuation. At 

 first sight this diatom resembles the C. erosus, Castr. var., but the 

 shape of the inter-radials is quite different, being regularly oblong 

 in Raeanus, while they are pouch-shaped and constricted towards 

 the margin in Castracane's form. The typical erosus, Castr., has a 

 quite different margin to the valves, as shown in the figures, so 

 that I do not hesitate in dedicating this species to my friend, 

 Mr. Rae, to whom I am greatly indebted for the specimens des- 

 cribed above, besides many other forms of diatoms. 



Campylodiscus Pantocsekii. Deby. 

 Group of Punctatae. 

 Diam. of valves, 0*156 m.m. 

 Diam. of area, 0*113 m.m. 

 Length of rays, 00 16 m.m. 



