~ 
Cc. A. BARBER. 
may be followed. The hypoderm, clear and starch-laden cells 
of the cortex, the collapsed layers, the protoplasmic cells ol 
the nucleus and the grandular epithelium are clearly separable. 
6. Cases of haustoria in the act of entering the host’s 
root are extremely rare. ‘This fact was noted in both Santalum 
and Olax, and it was suggested that the cause was to be sought 
in the rapidity with which the sucker penetrates the cortex. 
Among the numerous sections of haustoria examined in the 
preparation of this paper, only one such case has been met 
with, and that is an exceedingly minute haustorium, less than 
one-sixteenth of an inch in diameter. The sections were cut 
with the microtome, stained with Delafield’s hematoxylin 
and mounted in Canada balsam. They prove to be of much 
interest, and a detailed study of one of them is made on Plate 
EM: 
In the transitional region the vascular strands are well 
seen, but no vessels are yet formed, and the strands are thus 
procambial (a, e). A distinct hypodermal layer is visible in 
the upper part of the haustorium, although its contents are 
not well shown, The cortical cells within it are devoid of 
contents with the exception of delicate protoplasmic sacs (b). 
The cells of the ground tissue in the vascular loop are sharply 
separated from the nucleus: they are, as usual, elongated 
horizontally and have well marked nuclei but little protoplasm 
(c). Inthe haustorium proper, below the transitional region, 
the collapsed layers are clearly shown, although still very thin. 
The cortical cells outside them (f) are moribund and empty 
and have merely a trace of protoplasm here and there. The 
cells of the inner cortex have distinct protoplasm and nuclei 
(g), but, from the mode of preparation, the distribution of the 
starch grains is not easy to make out. It is to be noted that 
the collapsed layers in Cansjera do not proceed down the whole 
length of the cortical folds. They turn inwards and terminate 
at a point half-way between the edge of the fold and the 
sucker. This is characteristic of Cansjera and forms another 
