A FOSSIL MARINE DIATOMACEOUS DEPOSIT. 133 



striae (about 21 in '001"), the remainder of the surface being 

 quite clear. Length -0035" ; breadth of end lobes -001 // . (PI. 

 X, Fig. 11.) 



JV. lobata, n. sp., Gr. and St. — Valve constricted at centre. 

 Lobes oblong, with subacute ends. Median line distinct, with 

 small central and end nodules. Striae costate, conspicuous, not 

 reaching the median line, and absent for a considerable space in 

 the centre of the valve. Length "00475" ; breadth of lobes -0012". 

 (PI. X, Fig. 12.) 



N. placita, n. sp., Gr. and St. — Valve flat, oval, with broad 

 marginal belts of radial dotted striae, about 30 in , 001 // , leaving 

 between them a lozenge-shaped clear central space. Median 

 line very distinct with two central terminations rather wide 

 apart. Length -0023". Breadth -0013'/. This form has some 

 resemblance to N. patula, W. S. (" S. B. D.," PL 16, Fig. 

 139), but is broader, and has coarser striae. (PI. X, Fig. 14.) 



N. decora, n. sp., Gr. and St. — A very elegant form. Valve 

 oval, with rounded ends. Median line distinct, terminal nodules 

 dilated sideways. Striae distinctly dotted, parallel, about 18 in 

 001", leaving a narrow, clear space on each side of the median 

 line, which is slightly expanded at the centre. Towards the 

 margin the striae are interrupted by, first a narrow, and then a 

 broader clear space, the striae reappearing on the margin in the 

 form of a row of very short costae. Length "0047" ; breadth 

 •0019". (PI. X, Fig. 13.) 



Donkinia antiqua, n. sp., Gr. and St. — Frustule greatly con- 

 stricted. Valve ovo-lanceolate with subacute ends, occupying a 

 middle position in outline betwee D. compacta and D. carinifera 

 (" Pritchard," p. 921). Median line strongly sigmoid coincident 

 with the margin at the ends. Central clear space small, 

 circular. Striae rectilinear, about- 40 in •001". Length of valve 

 •0077". We regret that, owing to the only specimen of this 

 form discovered by Mr. R. Rattray having been injured after 

 this description was written, we are unable to figure this interesting 

 Diatom. 



Biddulphia ? fossa, n. sp., Gr. and St. — Valve flat, oval with 

 obtuse ends, in outline resembling Anaulus Mediterraneus, Grun. 

 (Pant., "Hungarian D.," PI. 18, Fig. 160). Processes inconspicu- 

 ous, scarcely more than slight elevations of the ends of the valve, 

 covered with finely clotted lines. Surface of valve dotted with 



