A FOSSIL MARINE DIATOMACEOUS DEPOSIT. 345 



Melosira oamaruensis, n. sp., Gr. and St. — This species, which is 

 abundant in the Oamaru deposit, belongs to the same group as M. 

 Sol. Ehr., and M. clavigera, Grun. The form, when touched, 

 readily breaks up into two discs, which differ from each other. We 

 give figures of both. The primary disc has a smooth margin, and 

 a clear centre, slightly raised. The margin is adorned with a ring 

 of closely set spathulate costal, in length about i th the diam. 



The secondary disc has a crenulate margin, and a border of 

 dotted striae, within which the costze are indicated by an annulus of 

 detached lines. Diam. to -006". (PI. XIII, Figs. 48, 49.) 



Pyxilla ? reticulata, n. sp., Gr. and St. — Single valves of this 

 little Diatom are not uncommon, but we have hitherto not observed 

 any complete frustules. Valve circular, slightly convex ; in frus- 

 tular view cylindrical, longer than the diameter. The whole surface 

 is hexagonally cellulate. (PI. XIII, Fig. 50.) 



Stoschial punctata, n. sp., Gr. and St. — We place here a form 

 which, judging from the figure of S. palacea, Grun. (" V. H. Syn. 

 Belg. Diat," PI. 128, Fig. 6), appears to have affinities with the 

 Genus. The surface is covered with small scattered granules. 

 Length -007". (PI. XIV, Fig. 52.) 



Tricerativm sexajiartitum, n. sp., Gr. and St. — A single speci- 

 men of this, for which we have to thank Herr Janisch, reached us 

 while correcting the proof of this paper. The valve has an 

 hexagonal outline, with obtusely rounded processes. The centre 

 is slightly depressed, and from this proceed very fine, thickly- 

 crowded, radiating lines of granules. Still liner granules cover 

 the processes, on each side of which are indications of internal 

 veins. Frustular view not yet observed. Diam '00345". (PL 

 XIV, Fig. 64.) 



Corrigenda. 



Opportunities of inspecting authentic examples of rare species 

 which have, since the publication of the earlier parts of this paper, 

 been afforded to us by the kindness of William Carruthers, Esq. 

 F.R.S., F. Kitton, Esq., Herr Janisch, and other friends, have 

 convinced us of the necessity of making a few changes in the 

 names recorded. These changes have, for the most part, been 

 indicated in the text, but we now give a summary of them. Our 

 readers will be so good, therefore, as to cancel — 



