476 PROF. D. H. CAMPBELL ON THE 
The single broad spiral band developed upon the wall of the 
elater seems to be a constant characteristic of the genus. The 
fully-developed elaters are packed in between the spores, and in 
stained sections are very conspicuous on account of the strongly 
stained spiral (fig. 19, el.). 
The outer cells of the capsule become much thickened at 
maturity, but differ a good deal in the two species examined. 
In D. Breutelii the cells were elongated with the lateral walls 
uniformly thickened. In D. erispus(?) they were shorter and 
the corners were thickened, so that they presented almost the 
appearance of typical collenchyma-cells. 
The dehiscence of the capsule is usually by two valves, as in 
Anthoceros, but sometimes there was a split on one side only. 
No stomata were observed in any instance, thus agreeing with 
Leitgeb’s conclusions as to their complete absence in Den- 
droceros. 
Summary and Conclusions. 
1. In its apical growth and the form of the thallus Dendroceros 
differs decidedly from the other genera of the order. The type 
of apical cell is that found in Pellia epiphylla and in the homo- 
sporous Ferns, especially Osmunda, where the prothallium 
resembles the thallus of. Dendroceros also in the definite midrib 
and the occasional development of leaf-like lobes. The oceurrence 
of abnormally large chloroplasts has been observed by the 
writer in O. cinnamomea, and may indicate a real relationship 
with forms like Dendroceros. 
2. The archegonium corresponds in its structure to that of the 
other Anthocerotaces, and is intermediate in character between 
Notothylas and Anthoceros. 
3. The antheridium is solitary and arises, as in the other mem- 
bers of the order, endogenously. The separation of the pedicel 5 
determined by the first division-wall in the young antheridium, 
and in this respect is more like that of JVofothylas than Antho- 
ceros, where this first arises after two longitudinal walls have been 
formed. The stalk may have either two or four rows of em l 
4. The first wall in the embryo is longitudinal, as 1m "nt 
ceros, but the first transverse wall determines the limits of the 
foot, as in JVotothylas. "£heci 
9. The origin of the archesporium is from the amphith eof 
as in the other two genera, but it is less massive than in either 
