40 Farmer. — Studies in Hepaticae : 
obvious segmentation parallel to its three sides (PL VI, Fig. 9) : 
on the other hand longitudinal sections, cut in the plane of 
the ground, exhibit an oblong structure, with apparently oblong 
segments given off parallel to the sides and inner face 
(PL VI, Figs. 3, 4, 6). Owing to the height of the cell, several 
consecutive sections can easily be cut through it, both longi- 
tudinally and transversely, and the results are consonant 
with the above formed conclusion as to its actual form. 
Sometimes however longitudinal sections exhibit an apical 
cell of apparently triangular outline, similar to that found in 
the foliose forms (PL VI, Fig. 5). But this appearance is due 
to the section having really traversed the large apical cell in 
an oblique direction, when of course this appearance would be 
produced. It is easy to convince oneself of the validity of this 
explanation by examination of serial sections. 
Apart from the appearance as shown by the transverse 
section, it might be argued that the cell really is a wedge- 
shaped one, as occurs, according to Leitgeb, in many frondose 
J ungermanniae, e. g. Blasia pusilla , and the triangular shape in 
longitudinal section would, of course, result in such a case 
if the plane of section happened to be parallel with one of the 
triangular sides of the wedge, whereas an oblong form would 
appear in sections passing through planes at right angles to 
this. But the fact that transverse sections of the apex 
exhibit the triangular form above described, disposes at once 
of this view, since a wedge-shaped cell with a triangular head 
could not exist as such, but would be converted into some- 
thing like a tetrahedron. 
The apex of Pellia epiphylla , according to Leitgeb’s 
description, accords somewhat with that of Pallavicinia 
decipiens , but in the former the prism is rectangular, and not 
triangular, in transverse section. Abscission of segments 
parallel to the innermost face of the cell is however a feature 
common to both. The form of segmentation prevailing in our 
plant, as will be seen by comparing Leitgeb’s figures \ differs 
in important characters from that exhibited by Pallavicinia 
1 Leitgeb, Unters. ii. d. Lebermoose, Heft III. 
