The writer's genusAcromastigum( I 0) illustrates terminal branching from both lateral and ventral segments and is the only genus of the Hepaticae with which the latter type of branching has been associated. The branches arising in this exceptional manner are flagelliform in character, and each shows at the base a narrow and incomplete underleaf. This represents the part of the segment that was not involved in the formation of the branch. In the writer's discussion of branching in the leafy Hepaticae (II, p. 23), terminal branching from ventral segments is definitely distinguished as the...