1894.) The Evolution of the Hepatice. 361 
knowledge. The present grouping into Musci and Hepatice 
as coordinate classes, is entirely unsatisfactory, and artificial. 
3. In such a triple development as exists among the He- 
patice, no single plant can stand as a type which will fairly 
represent the entire group. Ifa single plant is to be consid- 
ered, however, it would be only fair to make the selection 
from the group which is at once the most highly specialized 
structurally and the most widely represented in all parts o 
the world. To the Jungermaniales, and not to the Marchant- 
iales, belongs this distinction. 
4. We must recognize at least five families among the He- 
patice. Among the Jungermaniacez, it is well to separate 
those forms in which the archegone terminates the growth of 
the shoot from those in which the archegone is distinctively a 
lateral development. The ‘‘Jungermaniacee anakrogyne” 
of Leitgeb and Schiffner, which will include many but not all 
of the “‘Jungermaniacee thallose” of previous writers, may 
well be separated as a distinct family for which we propose 
the name METZGERIACE&. The older name, Jungerman- 
lacee, may properly be retained for the remaining part of the 
family which includes by far the greater number of genera and 
species. : 
5. The Hepatice are especially interesting as constituting 
the connecting link in the evolution from thallophytes (alge) 
to the higher plants. In this particular, the line of the An- 
thocerotales in which mere vegetative function is sacrificed 
for the sake of reproductive function, represents the royal line 
of development. 
¢ Pauw University, Greencastle, Ind. 
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