DADOXYLON. 191 



now referred. Some woods of this type have proved to belong to 

 Cordaites, while in the great majority of cases there is no evidence 

 as to the precise affinity of such specimens. 



It would seem probable that some of the Australian woods 

 described here may belong to Noeggerathiopsis, but at present there 

 is no definite evidence that this is the case. 



1. Dadoxylon australe, sp. nov. 



(Text-figs. 40-43.) 



Nicol 1 figured, in 1833, some transverse sections of petrified woods 

 from Australia. There are several similar sections in the British 

 Museum collection, most of which are obviously of the same tj'pe, 

 and these I propose to describe as Dadoxylon australe, since Nicol 

 did not give any name to his specimens. 



Co-types. — Transverse sections, 51,479 (Australia), 51,434 

 (Newcastle). Kadial sections, 51,616 (Australia), 51,476 (New- 

 castle). Tangential sections, 51,503 (Australia), 51,461 (New- 

 castle). Trans., Bad., and Tang, sections, V. 8299 (Australia). 



Pith not preserved. Xylcm with well-marked rings of growth, 

 each as a rule between 3"5 and S'5 mm. in radius. Some- 

 times the growth is irregular. The ' spring wood ' graduates 

 imperceptibly into the denser 'autumn wood.' Xylem com- 

 paratively dense, apparently entirely centrifugal. Tracheides, in 

 transverse section, very small, narrow, square, or slightly oblong, 

 with rounded angles, about 25 in a millimetre of length. 

 Tracheides short, with hexagonal bordered pits only on the radial 

 walls. Usually these pits are multiseriate and crowded, but not 

 infrequently they are found to be uni- or biseriate, distant or few. 

 Medullary rays extremely numerous, uuiseriate, very rarely two 

 cells thick, usually 6-12 or more cells in height. 



The medullary ray cells communicate with the tracheides by 

 2-6 simple, oblique pits. Cortex absent. 



It has not been found possible to identify the actual specimens 

 figured by Nicol, but they are probably among those mentioned 

 here. In describing this species, difficulty has arisen from the fact 



1 Nicol (33), pi. iii, fig's. 1-3. 



