a 'New Fern from the Coal-Measures. 2 i 3 
In addition to the spiral and scalariform elements shown in 
Figs. 9 and 10, the bundles contain large tracheids, with 
a distinctly reticulate form of pitting, like that figured in some 
of the Myeloxylon sections 1 . 
One of the longitudinal sections (C. N. 284) affords an 
example of the gradual convergence of two vascular bundles, 
separated by a wedge-shaped group of fundamental tissue 
which tapers towards the point of junction of the two concentric 
bundles. 
To return to the bundle-canals which have been noticed 
in the descriptions of Figs. 5, 6, and 7. These peripheral 
structures are well shown in Fig. 8, c. Fig. 11 shows under 
a higher magnification the two canals c m c iy of Fig. 7 : at c ni 
we have a group of small cells regularly placed round a central 
point ; they appear to be gradually separating from the centre, 
and remind us of a schizogenously formed canal in an early 
stage of development ; at c iy the canal has almost reached 
completion. In Fig. 12 we have two more canals, c v , c yi of 
Fig. 7 ; c y suggests a stage of development somewhat later 
than that of £ m , Fig. 11, and at c yi there are distinct indications 
of disorganization as well as cell-separation. Turning to 
Fig. 13 we find three stages of development of the canals, ^ vii , 
c ym , r ix , shown under a lower power in Fig. 6 ; c yii corresponds 
fairly closely to c m of Fig. 11 and Fig. 7 ; in both there is 
a slight accumulation of a dark substance in the space result- 
ing from the gradual separation of the cells : c yiii is probably 
a somewhat earlier stage than c y of Figs. 12 and 7, and in r ix 
we have the same indication of disorganization as in c iv , 
Figs. 11 and 7. It seems reasonable to conclude from the 
examination of a series of such examples as these, that the 
characteristic receptacles which accompany the vascular 
bundles of Rachiopteris Williamsoni are of the nature of 
small secretory canals formed as the result of a schizoly- 
sigenous process 2 . In one slide (C. N. 284) there is a solitary 
instance of a bundle-canal containing dark-coloured contents 
1 E. g. Ann. Bot., Vol. vii. PI. II, Fig. 18. 
2 Cf. Tschirch, Angewandte Pflanzenanatomie, 1889, p. 517. 
