n8 Worsdell. — On the Comparative Anatomy of 
through one of these tubers so as to pass through the root- 
cylinder, this latter will be seen in one part of it in either 
transverse or longitudinal section. The cortex has the same 
character as that of the root, containing starch-grains, &c. 
Besides the root-cylinder there will be seen one, two, three, or 
many bundles, which have a peculiar and striking appearance ; 
they are usually seen in transverse section ; in the centre are 
a few obscure xylem-elements ; surrounding these is a small 
zone of cells with very dense protoplasmic contents and 
conspicuous, large nuclei. These last-named cells are more or 
less isodiametric and angular, and when seen in longitudinal 
section are scarcely elongated ; the cells on their immediate 
outer limit, however, are rather more elongated and have 
not such dense contents. Outside these, again, is a conspicuous 
zone of cells with rather larger lumen and much clearer con- 
tents, containing much smaller yet distinct nuclei. Then 
follows an irregular grouping of cells, surrounding the last 
zone, with prominent dark nuclei and dense proteid contents. 
The first-described zone of dark-coloured cells, with the 
central xylem-group, represents the bundle ; this is always 
accompanied, however, by the two zones of cells last described 
(Fig. 5). These ‘ proteid-bundles 5 traverse the tuber in 
various directions, and may be seen running parallel to the 
root-cylinder or crosswise and at right angles to the latter. 
In some tubers all the cells of the ground tissue have very 
conspicuous nuclei ; while in most this is not the case, though 
the cells of the external layer are always thus characterized. 
Large agglomerations of stone-cells also occur throughout 
the cortex. 
In every case, when one of these tubers is examined, it will 
be seen that there is a portion of a Bamboo-root attached to 
it at some point (Fig. 3). If a series of sections be taken 
through a tuber, the ‘proteid-bundles’ can be traced till they 
eventually bend outward, and, two or more fusing together 
into one, enter a haustorium which is penetrating the host- 
root. Thus, the haustorial bundle, on entering the tuber, 
instead of passing directly to the central cylinder, branches, 
