EvANS: HEPATICAE OF PUERTO RICO 211 
line, very much as in Cololejeunea and its immediate allies. They 
spread widely from the axis and lie more or less appressed to the 
substratum, although in some species they are distinctly convex. 
They vary in outline from ovate to suborbicular, their apices are 
broad and rounded, their margins are entire or nearly so, and they 
tend to arch across the axis at the antical base. The cells of 
the lobes are plane or nearly so, and their walls are more or less 
thickened. In some species the thickening appears to be uniform, 
while in others trigones and intermediate thickenings are clearly 
visible. In all the Puerto Rico species ocelli are numerous and 
scattered throughout the lobe, very much as in the genus Stictole- 
jeunea. They are found also’ in the perianths but seem to be 
constantly absent from the lobules and underleaves. In D. 
pellucida the lobes are often margined by a band of hyaline cells, 
t these have not been observed in the other species. 
The lobule agrees in many respects with that of Cololejeunea. 
It is of a fairly large size, from one third to one half the length 
of the lobe, and is inflated throughout more or less of its extent. 
It broadens out abruptly from a narrow base and forms a distinctly 
arched keel with the lobe. The free margin is involute in its 
basal portion and sometimes for about half its length, the outer 
part being frequently appressed to the lobe. At some little dis- 
tance beyond the middle the apical tooth is situated and is sepa- 
rated from the end of the keel by a shallow sinus. The tooth is 
remarkably well developed and shows considerable variation in 
orm. It may, for example, be subulate and acuminate (FIGURES 
Tand 5) orit may broaden out from a stalklike base into a t-shaped 
Structure (FIGURES 10 and 13). The hyaline papilla is situated 
at the base of the tooth on the inner surface of the lobule. When 
a of the tooth is three cells wide the papilla is on the median 
a a the tooth is two or four cells wide it is situated on one 
‘ the median wall, sometimes on the distal side and some- 
piigioas the proximal. In addition to the apical tooth the free 
Margin bears a second tooth, proximal to the apex; this tooth is 
shor : 
ter than the apical tooth and also different inform. Between 
“i Proxim, 
vie nal tooth and the base of the lobule one or more minute 
Culations may be distinguished in certain species. 
underleaves are sometimes distant and sometimes overlap 
