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XXVIL— On the Fossil Osmundacese. By R. Kidston, F.R.S. L. & E., F.G.S., 

 Foreign Mem. K. Mineral. Gesell. zu St Petersburg ; and D. T. Gwynne- 

 Vaughan, M.A., Lecturer in Botany at Queen Margaret College, Glasgow 

 University. (Plates I.-VI.) 



(MS. received November 16, 1906. Read February 4, 1907. Issued separately July 5, 1907.) 



PART I. 



The two new species of Osmundites described in this paper are based upon two 

 fossils from the Jurassic rocks near Gore, Otago district, New Zealand. The one was 

 discovered by Mr Robert Dunlop, and the other by Mr Robert Gibb. Both specimens 

 eventually came into the possession of Mr Dunlop, who generously handed them over to 

 the authors for investigation, with full permission to have them cut for microscopical 

 examination, and to whom we take this opportunity of expressing our indebtedness. 



Osmundites Dunlopi, n.sp. 

 (Plates I., II., and III., figs. 1-16.) 



The specimen is preserved in silica, and the plant appears to have suffered a certain 

 amount of decay and attrition before it finally became embedded in the rock. The 

 fossil was collected in situ, and impressions of the leaves of Cladophebis denticulately 

 Brongt. sp., were also found in the same bed. The specimen measured 9 cm. across its 

 widest, and 6 cm. across its narrowest part, and contained a portion of the stem about 

 3 cm. long. The stem itself was to be seen in transverse section on both surfaces of the 

 block ; but the greater part of the fossil consisted of a very large number of overlapping 

 leaf-bases packed closely round the axis (PL I., fig. 1). The stem itself is about 17 mm. 

 in diameter, and its external limit is indicated by the letter a in the figure. The outer 

 region of the cortex is sclerotic, and stands out clearly even in surface view. 



Fig. 2, PI. I., is a photograph of a transverse section, and it shows that, while the 

 sclerotic tissues are fairly well preserved, the thin-walled tissues had decayed before 

 fossilisation, leaving spaces now filled with finely granular matter in which the cellular 

 structure is only rarely indicated. In no case, however, do these spaces represent 

 actual lacunae, and it may be safely assumed that in life they were occupied by thin- 

 walled tissues analogous to those present in the corresponding regions in the other 



species of the order. 



TRANS. ROY. SOC. EDIN., VOL. XLV. PART III. (NO. 27). 108 



